Mew @ Leftovers
Ability: Synchronize
EVs: 252 HP / 148 SpD / 108 Spe
Calm Nature
IVs: 0 Atk
- Taunt
- Will-O-Wisp
- Night Shade
- Roost
+1 4 SpA Reuniclus Psychic vs. 252 HP / 148+ SpD Mew: 69-82 (17 - 20.2%)
+1 4 SpA Reuniclus Psychic vs. -1 252 HP / 148+ SpD Mew: 104-123 (25.7 - 30.4%)
+1 4 SpA Reuniclus Psychic vs. -2 252 HP / 148+ SpD Mew: 138-163 (34.1 - 40.3%)
+1 4 SpA Reuniclus Psychic vs. -1 252 HP / 148+ SpD Mew on a critical hit: 208-246 (51.4 - 60.8%)
Mew is an excellent counter to this reuniclus - it can switch in on any move and prevent further calm minds or recovery with taunt. You can whittle away with night shade / stall out psychic and focus blast pp quite easily in sand barring horrendous luck. Even if you get dropped once and then crit, you will be ok provided you were above 60.8 + 6.25% health in sand, which is achievable alternating roost and taunt at -1. If you get dropped twice early, hopefully you have something else to switch into the plus one psychic to reset the drops, then switch back in and deal with the +2 reun.
+2 0 SpA Reuniclus Psychic vs. 252 HP / 148+ SpD Mew: 93-109 (23 - 26.9%)
Reuniclus will generally be found on sand teams, and mew also does an excellent job of pressuring some typical examples. Tyranitar hates wisp so has difficulty pursuit trapping it, and other hard physical hitters on sand such as excadrill and lando-t are also ruined by a wisp, which differentiates this from celebi for example. Gastrodon, skarmory, jellicent, ferrothorn and other defensive sand staples barring heatran / toxic orb gliscor all lose to non toxic'd Mew. Once your mew has switched into the reuniclus, it is on the cards that reun will switch out at some point especially once taunted, giving you the chance to try and make a read and land a crippling wisp on something else. It's also nice to have as a solid Alakazam check and non specs / cm latios check, common psychic partners for Reuniclus.
252 SpA Alakazam Shadow Ball vs. 252 HP / 148+ SpD Mew: 142-168 (35.1 - 41.5%)
This EV spread outspeeds plus speed base 70s like breloom and lead skarm and neutral base 80s like mamoswine to get the wisp / taunt off, EVs can be moved from Sp Def to speed and even plus speed natures can be used to wisp pokemon such as landorus before they u-turn, however in this case this would adversely affect mew's ability to counter reuniclus and other special attackers. Ice beam could also be used over night shade for gliscor and other 4 times weak mons, as you can still stall reuniclus pp without night shade.