The excellent Jello is your man for the job.
Jellicent @ Leftovers
Trait: Water Absorb
EVs: 252 HP / 128 Def / 128 SDef
- Surf
- Will-O-Wisp
- Taunt
- Hex
Jellicent not only resists those fighting STABs, but also cripples those three. Surf deals with Nape, and has swell power. Will-O-Wisp puts in status. Taunt says trolled to SDance. Hex is STAB plus x2 power.
Seeing you have Umbreon, Trick room is a viable option as well. Trick Room teams screw the three main OU fighters.