Sinistea-Antique @ Weakness Policy
Ability: Weak Armor
EVs: 244 SpA / 4 SpD / 196 Spe
IVs: 0 Atk
- Stored Power
- Shell Smash
- Giga Drain
Endure is here so weakness policy + weak armor is basically a shell smash on its own, and it doesn't require focus sash for setup.
The main downside is that it requires the opponent to trigger (almost always with a knock off), which is why the shell smash is also here in case it requires setting up by itself.
Alternatively, you could set up on the activation of the weakness policy + weak armor if you know that you'll survive through a super effective attack for a high risk/high reward sweeper.
Stored power is self-explanatory, and benefits even more from the aforementioned alternative setup strategy.
Giga drain allows for recovery after endure is used, given that you will most likely be at very low hp.
(A main weakness of this set is matchups against pawniard, since sucker punch allows priority OHKO.)