I've found that you need two things to defeat most Sun teams.
1. Some hazards. (SR is enough.)
2. Ninjask.
What?
Sun sweepers are really, really fast. But in Tier Shift, there is nothing faster than Ninjask, whizzing by at a blistering base 185 speed. There are a lot of Pokemon that don't have an actual speed stat that high.
"But Infernis!", you might be exclaiming, "Chlorophyll doubles the speed of its users! Not even Ninjask can outrun that!"
Not at first. Normally, Ninjask uses his speed boosts to speed up an allied sweeper. But with this set, he takes advantage of the ability for himself in order to lay down some serious hurt.
Ninjask@Expert Belt
Stats: 76/105/60/65/65/185
EVs: 252 Atk/8 Def/248 Spe
Nature: Adamant
-X-Scissor
-Aerial Ace
-U-turn
-Protect
It's pretty straightforward. X-Scissor and Aerial Ace are the strongest STAB moves Ninjask has. U-turn lets him deal heavy damage and still get away if he can't quite KO the enemy sweeper. Protect lets him get a free speed boost, meaning that nothing in the entire game except max speed Jumpluff outruns him in the sun. (Floatzel can outrun him in the rain until two boosts are obtained.)
Max Speed Sawsbuck hits 700 speed in the sun. Jumpluff hits 766 as the fastest Chlorophyll user. (Neutral natures give 634 and 698 respectively.) Unfortunately, max speed Ninjask misses out on outrunning max speed Jumpluff by a mere two points after one turn of speed boost. If you manage to get more than one speed boost by the time Jumpluff shows up, you're golden.
EDIT: I lied, Whimsicott ends up with a base 126 speed, slightly higher than Jumpluff. But Ninjask can't outrun Jumpluff anyway.
Ninjask hits a staggering 406 speed with an Adamant nature and no investment and needs 248 speed EVs to outrun Jolly Sawsbuck in the sun.
Now, damage calcs. (Using the Honkalculator with manually edited base stats.) Listed in order of base speed:
Only the most defensive of Jumpluff survive Aerial Ace, which deals 63-75%. Offensive Jumpluff (the ones you can't outrun) are always OHKO'd after Stealth Rock damage.
252+ Atk Expert Belt Ninjask X-Scissor vs. 112 HP / 0 Def Sawsbuck: 341-403 (94.98 - 112.25%) -- 68.75% chance to OHKO. With no HP investment, always a KO. (Any hazard always guarantees it!)
X-Scissor 2HKOs all forms of Leafeon, ranging from dealing 60% to bulky sets to a whopping 76-91% for standard offensive sets. Max speed/attack Leafeon has an 18.75% chance to be OHKO'd.
Leavanny is always OHKO'd by Aerial Ace, not that anyone's using it. Well, a max HP/Defense set (trololo) only has a 75% chance to be OHKO'd. Watch out for that.
X-Scissor and usually U-Turn will slay offensive Quiver Dance Lilligant instantly, but weird maximum bulk sets are only narrowly 2HKO'd unless you have both SR and a layer of spikes down.
Shiftry will be instantly slain by X-Scissor and U-turn, but watch out! Max Attack Shiftry has an 18.75% chance to OHKO Ninjask with Sucker Punch. If you suspect that sort of Shiftry, don't risk Ninjask at anything other than full health.
Ninjask has a 56.25% chance to OHKO offensive Victreebel after Stealth Rock by using Aerial Ace, but otherwise is limited to always 2HKO'ing bulkier sets. Luckily, nobody wants to make a bulky sweeper out of 95/80/75 defenses.
I have no idea why anyone would use Maractus in this tier, but even very bulky sets are always OHKO'd by X-Scissor after stealth rock.
Eviolite Tangela is for suckers, but only takes 33.6-39.66% damage from X-Scissor. That's always a 3HKO, but I guess you can revenge kill it. (U-Turn can be used for repeated 28-34% damage if it's not healing and is somehow plowing through your team.)
X-Scissor and U-Turn both OHKO all forms of Exeggutor.
Aerial Ace will only 2HKO bulky Tropius, and SR is recommended to guarantee that. (Since bulky sets are often subseeders.) After SR damage and a substitute, Ninjask can easily finish it off. Offensive Growth sets are always OHKO'd after Stealth Rock.
Tank Tangrowth (252 HP/Def) will only take 41-49% damage from Ninjask's X-Scissor, but is always 2HKO'd by both that and U-Turn after SR damage. Offensive Tangrowth are 2HKO'd by both X-Scissor and U-turn, SR or no.
The bulkiest Vileplume are always 2HKO'd (51-59% damage) by Aerial Ace. SpA/Spe focused Vileplume sweepers are always OHKO'd after Stealth Rock.
X-Scissor has a 56.25% chance to OHKO offensive Bellossom, even before rocks. Bulky Bellossom will only be 2HKO'd, even with SR damage. (62-73% damage)
X-Scissor and Aerial Ace will both OHKO Sweeper Sunflora. If you're fighting someone with the gumption to run a max HP/Defense Sunflora in the sun, well, you only have a 25% chance to KO after Stealth Rock. (Though that's still a guaranteed KO if they have Solar Power.)
Ninjask will not do well against Charizard and Chandelure. SR damage lets him 2HKO Charizard or Chandelure after SR damage, but it's best to U-turn away to Quagsire or something. (Or your own Sawsbuck/other Sap Sipper, if you expect a Solarbeam.) If it's a Chlorophyll sweeper, Ninjask can beat it or wear it down. If it's a fire type taking advantage of the sun, run the fuck away.
EDIT: Forgot Venusaur and Whimsicott in there.
Venusaur: Aerial Ace has a 18.75% chance to OHKO offensive Venusaur before hazards. Get any kind of non-toxic-spike hazards down and it will surely fall. Luckily, the only common defensive variants are specially defensive subseed sets. Aerial Ace deals only 72-85% to that variety, but a combination of SR and a layer of spikes will cause even that to fall.
Whimsicott: Run! Well, maybe. If it's a bulky supporting prankster set, stun spore will kill Ninjask's one excellent stat. If you have a cleric to fix that up, X-Scissor and U-Turn both deal heavy damage, though not quite a KO. (64-76% for X-Scissor.) If you happen to have rocks and two layers of spikes down, a OHKO becomes possible. If it's an offensive chlorophyll set, which isn't entirely impossible for people who need to go first, things look a little better. Ninjask can OHKO with X-Scissor, even without hazards. Just make sure to get two boosts instead of one, first.
Asides from spikes, Ninjask appreciates Sap Sippers, since they'll fairly well counter Jumpluff and Whimsicott. (Or simply teammates that are immune to paralysis or sleep.)
1. Some hazards. (SR is enough.)
2. Ninjask.
What?
Sun sweepers are really, really fast. But in Tier Shift, there is nothing faster than Ninjask, whizzing by at a blistering base 185 speed. There are a lot of Pokemon that don't have an actual speed stat that high.
"But Infernis!", you might be exclaiming, "Chlorophyll doubles the speed of its users! Not even Ninjask can outrun that!"
Not at first. Normally, Ninjask uses his speed boosts to speed up an allied sweeper. But with this set, he takes advantage of the ability for himself in order to lay down some serious hurt.
Ninjask@Expert Belt
Stats: 76/105/60/65/65/185
EVs: 252 Atk/8 Def/248 Spe
Nature: Adamant
-X-Scissor
-Aerial Ace
-U-turn
-Protect
It's pretty straightforward. X-Scissor and Aerial Ace are the strongest STAB moves Ninjask has. U-turn lets him deal heavy damage and still get away if he can't quite KO the enemy sweeper. Protect lets him get a free speed boost, meaning that nothing in the entire game except max speed Jumpluff outruns him in the sun. (Floatzel can outrun him in the rain until two boosts are obtained.)
Max Speed Sawsbuck hits 700 speed in the sun. Jumpluff hits 766 as the fastest Chlorophyll user. (Neutral natures give 634 and 698 respectively.) Unfortunately, max speed Ninjask misses out on outrunning max speed Jumpluff by a mere two points after one turn of speed boost. If you manage to get more than one speed boost by the time Jumpluff shows up, you're golden.
EDIT: I lied, Whimsicott ends up with a base 126 speed, slightly higher than Jumpluff. But Ninjask can't outrun Jumpluff anyway.
Ninjask hits a staggering 406 speed with an Adamant nature and no investment and needs 248 speed EVs to outrun Jolly Sawsbuck in the sun.
Now, damage calcs. (Using the Honkalculator with manually edited base stats.) Listed in order of base speed:
Only the most defensive of Jumpluff survive Aerial Ace, which deals 63-75%. Offensive Jumpluff (the ones you can't outrun) are always OHKO'd after Stealth Rock damage.
252+ Atk Expert Belt Ninjask X-Scissor vs. 112 HP / 0 Def Sawsbuck: 341-403 (94.98 - 112.25%) -- 68.75% chance to OHKO. With no HP investment, always a KO. (Any hazard always guarantees it!)
X-Scissor 2HKOs all forms of Leafeon, ranging from dealing 60% to bulky sets to a whopping 76-91% for standard offensive sets. Max speed/attack Leafeon has an 18.75% chance to be OHKO'd.
Leavanny is always OHKO'd by Aerial Ace, not that anyone's using it. Well, a max HP/Defense set (trololo) only has a 75% chance to be OHKO'd. Watch out for that.
X-Scissor and usually U-Turn will slay offensive Quiver Dance Lilligant instantly, but weird maximum bulk sets are only narrowly 2HKO'd unless you have both SR and a layer of spikes down.
Shiftry will be instantly slain by X-Scissor and U-turn, but watch out! Max Attack Shiftry has an 18.75% chance to OHKO Ninjask with Sucker Punch. If you suspect that sort of Shiftry, don't risk Ninjask at anything other than full health.
Ninjask has a 56.25% chance to OHKO offensive Victreebel after Stealth Rock by using Aerial Ace, but otherwise is limited to always 2HKO'ing bulkier sets. Luckily, nobody wants to make a bulky sweeper out of 95/80/75 defenses.
I have no idea why anyone would use Maractus in this tier, but even very bulky sets are always OHKO'd by X-Scissor after stealth rock.
Eviolite Tangela is for suckers, but only takes 33.6-39.66% damage from X-Scissor. That's always a 3HKO, but I guess you can revenge kill it. (U-Turn can be used for repeated 28-34% damage if it's not healing and is somehow plowing through your team.)
X-Scissor and U-Turn both OHKO all forms of Exeggutor.
Aerial Ace will only 2HKO bulky Tropius, and SR is recommended to guarantee that. (Since bulky sets are often subseeders.) After SR damage and a substitute, Ninjask can easily finish it off. Offensive Growth sets are always OHKO'd after Stealth Rock.
Tank Tangrowth (252 HP/Def) will only take 41-49% damage from Ninjask's X-Scissor, but is always 2HKO'd by both that and U-Turn after SR damage. Offensive Tangrowth are 2HKO'd by both X-Scissor and U-turn, SR or no.
The bulkiest Vileplume are always 2HKO'd (51-59% damage) by Aerial Ace. SpA/Spe focused Vileplume sweepers are always OHKO'd after Stealth Rock.
X-Scissor has a 56.25% chance to OHKO offensive Bellossom, even before rocks. Bulky Bellossom will only be 2HKO'd, even with SR damage. (62-73% damage)
X-Scissor and Aerial Ace will both OHKO Sweeper Sunflora. If you're fighting someone with the gumption to run a max HP/Defense Sunflora in the sun, well, you only have a 25% chance to KO after Stealth Rock. (Though that's still a guaranteed KO if they have Solar Power.)
Ninjask will not do well against Charizard and Chandelure. SR damage lets him 2HKO Charizard or Chandelure after SR damage, but it's best to U-turn away to Quagsire or something. (Or your own Sawsbuck/other Sap Sipper, if you expect a Solarbeam.) If it's a Chlorophyll sweeper, Ninjask can beat it or wear it down. If it's a fire type taking advantage of the sun, run the fuck away.
EDIT: Forgot Venusaur and Whimsicott in there.
Venusaur: Aerial Ace has a 18.75% chance to OHKO offensive Venusaur before hazards. Get any kind of non-toxic-spike hazards down and it will surely fall. Luckily, the only common defensive variants are specially defensive subseed sets. Aerial Ace deals only 72-85% to that variety, but a combination of SR and a layer of spikes will cause even that to fall.
Whimsicott: Run! Well, maybe. If it's a bulky supporting prankster set, stun spore will kill Ninjask's one excellent stat. If you have a cleric to fix that up, X-Scissor and U-Turn both deal heavy damage, though not quite a KO. (64-76% for X-Scissor.) If you happen to have rocks and two layers of spikes down, a OHKO becomes possible. If it's an offensive chlorophyll set, which isn't entirely impossible for people who need to go first, things look a little better. Ninjask can OHKO with X-Scissor, even without hazards. Just make sure to get two boosts instead of one, first.
Asides from spikes, Ninjask appreciates Sap Sippers, since they'll fairly well counter Jumpluff and Whimsicott. (Or simply teammates that are immune to paralysis or sleep.)