(typing this in phone, so ymmv)
Garchomp @ Dragonium Z
Ability: Sand Veil
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Stealth Rock / Substitute / Fire Blast / Poison Jab
- Earthquake
- Outrage
- Swords Dance
Tyranitar @ Shuca Berry / Smooth Rock
Ability: Sand Stream
EVs: 252 HP / 88 SpA / 168 SpD
Modest Nature
- Thunder Wave
- Toxic / Stealth Rock / Pursuit
- Ice Beam
- Fire Blast
Special support lure ttar is a perfect partner to facilitate a garchomp sweep. TTar and Chomp typically share similar switch-ins, but this set takes advantage of that to lure and KO them.
Thunder Wave cripples threats who could outspeed and revenge chomp. Parahax is obviously useful for slower mons as well, and it can earn Garchomp some nice free turns. This TTar can tank and paralyze the vast majority of relevant mons (for example, scarf lele only 3hkos with moonblast), making garchomp immediately more threatening.
Toxic is another unexpected move that can cripple some common defensive switch-ins. This slot can be replaced with rocks to free up an extra garchomp move.
Pursuit also works (with a slight ev tweak probably) to get some guaranteed damage off on a mon to potentially secure a 1hko/2hko in the future. For example, with 0 attack modest, it does around 20% to Chansey on the switch out. This puts Chansey just barely in KO range for +2 earthquake and +0 devestating drake. Otherwise, it would cleanly live either hit.
Ice Beam with this EV spread 1hkos all lando-t sets, who is otherwise an immense annoyance to chomp and every other physical sweeper. It also 1hkos zygarde and garchomp, so with shuca berry, ttar can be a nice emergency check to both (takes 50% from +1 zygarde with shuca and lived +2 eq from chomp). Nothing more to say; ice beam is ice beam.
Fire blast cleanly 1hkos mega scizor with these EVs, and it does ~75% to both ferro and physically defensive tangrowth. Celesteela takes 46% max (ie it's still a bulky annoying fuck), but that's not an insignificant amount. In fact, it puts celesteela in range to be 1hokd by +2 devestating drake, or even +2 fire fang with a bit more prior damage (considering leftovers recovery, etc). Solidly 2hkos offensive magearna, and is a great option to catch mag on a switch (plus, you comfortably device max SpA fleur cannon!). Lets ttar be an emergency excadrill check too, as it does a solid 80% while excadrill can't KO through shuca, even when boosted.
Shuca adds a ton to ttars utility as a lure considering his biggest target is a ground type. Lets him check zygarde, garchomp, and exca too as mentioned before. Soft sand is an alternative option to extend sand for garchomp, exca, etc to abuse. The extra chip damage from those sandstorm turns is super appreciated when trying to wear down the opposing team.
Made the obligatory rough skin -> sand veil change to garchomp. In sand, it's an arguably superior ability (see: garchomp being banned to Ubers until rough skin was released and sand veil was banned). In this core where ttar is there to lure and kill most of the common u-turn users anyway (and tapu Koko is great setup bait for potential teammate excadrill), sand veil is almost certainly superior. Every move directed at garchomp during sand has its accuracy multiplied by 0.8. in other words, 100% moves become hydro pump, and 90% moves become only marginally better than focus blast. Don't actively rely on it to secure your sweep, but it massively skews the odds in your favour at clutch moments, and it can make up for failing to remove a problematic garchomp check earlier in the game.
If you choose to give ttar rocks, then chomp's first slot can be changed to fire coverage, poison coverage (bulu), or substitute to let you set up in the face of passive mons with the side benefit of maximising sand veil effects.
