First of all, thanks to everyone who helped my P2 set win! As for this week, with already 273 sets posted, I'm surprised my idea hasn't already been taken...
Best offensive tanky Swampert set ever. Period.
Dunkleosteus (Mixed Special Tank)
Swampert @ Assault Vest
Ability: Torrent
EVs: 240 HP / 244 SpA / 16 SpD / 8 Spe (recommended)
Quiet Nature
- Earthquake
- Scald
- Ice Beam
- Superpower / Hammer Arm
Special-biased mixed Swampert. Surprising, I know, but very effective. Swampert, while sporting an Assault Vest, can now tank special hits amazingly well, even with little investment. To put it in perspective, this Swampert has just slightly more special bulk than 240/252+ Jirachi, amazing. Despite forgoing support moves, Swampert still offers amazing utility, spreading burns with Scald, which hurts a lot with heavy investment. Ice Beam OHKOs Mega Sceptile and 2HKO's every other Grass type in the tier, doing upwards of 60% minimum to all but defensive Roserade, which can't take 2 Earthquakes anyway. Earthquake, even though not invested, hits specially bulky targets hard, namely Empoleon and Tentacruel. Earth Power is viable to smack a few Ground-weak Pokémon harder, like Doublade. Superpower exists mostly to eliminate Mega Abomasnow, but can also deter Umbreon and Blissey from switching in, even though they can't beaten while moderately healthy.
EVs maximize bulk and special attack, while throwing a few in SpD to squeeze a little more value out of Assault Vest. 8 Speed EVs creep M-Abomasnow and other Mons that invest in speed to outrun Relaxed Swampert. 48 SpD EVs gain noticeable more special bulk, so moving the EVs from SpA is an option.
I'll post some calcs and replays later, but this thing is downright terrifying, especially with Wish and cleric support. Being able to switch into UU's powerhouses, even Hydreigon, while also offensively threatening everything but the sturdiest of special walls is amazing. Only a handful of UU Pokémon don't mind switching in, and they all are so passive that a stallbreaker makes easy work of all of them.