Prankster Liepard has some fun options and I want to get some opinions on it. It has priority Nasty Plot, Trick, Yawn, Encore, Hone Claws and Substitute.
One idea would be to Trick a Flame Orb onto a physical attacker. Or a Choice Scarf onto a wall. You don't need to invest in Speed EV's, so it could possibly survive a hit and cripple something with Trick.
Or maybe give it a Focus Sash, use Yawn, then Protect or Subsitute, and then you can Thunder Wave or Toxic the switch, crippling two members of your opponent's team.
I also think Sharpedo deserves some love. It can hit extremely hard and fast with Speed Boost and STAB water attacks in Rain. It has access to priority, and can pull off surprise KO's with Ice Beam on those pesky dragons with its base 95 special attack. It can run mixed sets or dedicated special or physical sets, with access to Hydro Pump, Scald, Surf, Dark Pulse, Ice Beam, Earthquake, Crunch, Ice Fang, Aqua Jet and Waterfall.
Edit: tested some sets:
Liepard
@ Focus Sash
Prankster
Adamant
252 HP / 252 Atk / 4 Def
- Yawn
- Protect / Substitute
- Sucker Punch
- Knock Off / Thunder Wave
Because of Prankster, no investment in speed EV's is necessary (giving Liepard maximum Atk and HP), and every move on the set gets priority. Use Yawn and then Protect / Substitute to put the foe asleep. Yawn often forces a switch, so Substitute would be better in theory. But I have found that Protect is usually better because with Focus Sash equipped, Liepard often has 1 HP and can't use Substitute, and they don't always switch after Yawn anyway. Sucker Punch deals some nasty damage and can KO weakened foes. Once the foe is asleep, you would expect your opponent to switch in something else. That's when Thunder Wave or Knock Off becomes handy to cripple the switch in. I prefer Knock Off because often the opponent prefers not to switch for some reason, rendering paralysis useless.
I've tested this set and it can pull of surprise KO's, put something to sleep, and cripple enemy sweepers and walls with Knock Off.
Sharpedo
@Focus Sash
Mild (lowers Def, raises SpA)
Speed Boost
148 Atk / 252 SpA / 108 Spe
- Protect
- Ice Beam
- Dark Pulse / Hydro Pump / Surf
- Aqua Jet
Nobody expects a Specially offensive Sharpedo (even though it has 95 base SpA). And because of that, everybody underestimates it. This thing is a monster. Protect + Speed Boost is the obvious first turn move usually, and after that it just becomes carnage. Ice Beam destroys just about every threat in the OU metagame. Thunderus, Tornadus, Landorus, Breloom, Virizion, Dragonite, Salamence, Haxorus, Hydreigon, Venusaur, Zapdos, Gliscor, Tangrowth, Hippowdon, Amoonguss, you name it. Anything that isn't OHKO'd is simply 2HKO'd thanks to Focus Sash. It's hilarious watching people switch in a Sharpedo counter expecting to be hit with a Waterfall or Crunch, and then watching their monster die to Ice Beam.
Dark Pulse I find the best STAB option thanks to it's flinching effect and ability to hit annoying Ghosts. I go with Aqua Jet in the last slot because even after all those speed boosts, you need a priority attack to pick of weakened foes or beat other priority users, in particular those packing Mach Punch or Vacuum Wave. Plus Aqua Jet gets STAB and is boosted in Rain, and my nature doesn't dent Sharpedo's impressive 120 base Atk. I love this set and I have swept entire teams with it.
Milotic
@Leftovers / Life Orb
Calm
Marvel Scale
252 HP / 124 SpA / 132 SpD
- Scald
- Ice Beam
- Recover
- Dragon Tail / HP Electric / Haze / Toxic
I am still perfecting the EV's for this set. I need it to be able to take special hits and be able to dish out the damage in return. But basically, Scald is the STAB attack, boosted in rain, good coverage, and burns the foe a lot of the time, protecting Milotic's weak Def stat. Ice Beam is their to deal with the pests of the OU metagame (see Sharpedo's description). And Recover is obvious. The last slot I give to Dragon Tail because it is just so useful. If you have multiple entry hazards set up, a bulky Milotic with Dragon Tail can be about the most frustrating thing there is, phazing pokemon and racking up lots of damage. It stops pokemon powering up (eg. Dragon Dancers, Quiver Dances, Swords Dancers, Calm Minders), it gets rid of special walls (read: Chansey and Blissey), and it even gets past Taunt. The other great thing about Milotic is that she doesn't mind switching into a T-Wave or Toxic. She can take hits, score surprise KO's with Ice Beam, and cause huge headaches with Scald and Dragon Tail.