Sylveon @ Leftovers
Ability: Cute Charm
EVs: 252 HP / 252 SDef / 4 Def
This girl (guuuurll) is a fine special sponge. It can't take physical hits too well, but if it does there is Cute Charm to try and retaliate, but its too unreliable considering it may not actually activate, it maybe the wrong gender match up, and it might just fail altogether. Yet you see me using it.
Moonblast is a more defensive move with a 30% to lower the opponent's Special Attack which makes it easier for Sylveon to sponge those hits a lot easier. It also gets exactly 8 more PP then Hyper Voice, which might not say much, but occasionally you might run into that issue late in the game where those 8 hits count.
Wish passing can be invaluable to a team. Most of the time it'll help you gain some strong momentum on a switch as it can stop a potential 2HKO. Protect ensures that Sylveon can get a Wish herself. Toxic can devastate any Pokemon it works against. Put these together and you end up with stall.