I'm thinking a set like this could have some merit-
Trevenant @ Sitrus Berry
Harvest
Careful
252 HP/ 4 Atk/ 252 SpD
-Horn Leech
-Shadow Claw
-Curse
-Protect
The nature and EV's are whatever, but the idea is to switch in on something that can't hurt it, then Curse on the switch out. Curse...