Anything you can do I can do betterr~
@ Leftovers
Ability: Water Absorb
Tera Type: Dark
EVs: 252 HP / 252 Def / 4 SpD
Relaxed Nature
IVs: 0 Spe
- SpA absuing move, depends on PP
- Flip Turn
- Wish
- Copycat
Tera Dark + Water Absorb walls the posted set completely.
On the one hand, you can utilize the double immunity + slow flip-turn to heal your entire team as they waste valuable PP. On the other, you can set up alongside them if you time copy-cat right. This is a war-of-attrition approach, and as they run out of PP for moves, they are forced to go into moves which get Copy-Catted. With Copy Cat as the last move, this is effectively a 6-7 move set, as we're happy to copy any of their moves save an early stored power.
Realistically, when manaphy comes in and goes for a boost and sees Vaporeon, it won't go for scald, it'll be too early to stored power, so it will go for boost. Using Copy Cat mirrors what they do, including boosting SpD to somewhat neutralize stored power. Depending on how risky you want to play, you can Tera on low-hp as they think they're about to kill Vaporeon, and go for the Copy-Cat on their attacking move.
The first slot is vague because it logically could be scald, or scald can be called from CopyCat. This is an attrition strategy, so high-pp/low-damage moves are very good there as well. Mainly, the existence of this Vaporeon turns Manaphy into a liability, because it becomes a free Wish-Turn, for as long as manaphy remains in. The free wish-turn also helps the PP war, because the sequence has a net -1 PP for the opponent as they go for a move on your switch into vaporeon.
This is hard to justify as a lure, but Manaphy has nothing to fear from the average Vaporeon, making it seem like an ideal set-up target. This is the way Manaphy is lured, though it is not obvious, and there is no damage threat from vaporeon, rather, a utility threat that is a Super-Revival-Blessing as long as it sits on Manaphy.