Exeggutor

Chlorophyll
Speed doubles in sun.
Type Tier
Grass / Psychic BL
Level 100 Statistics (see level 5, 50, 100)
Min- Min Max Max+
HP
95
- 331 394 -
Atk
95
203 226 289 317
Def
85
185 206 269 295
SpA
125
257 286 349 383
SpD
65
149 166 229 251
Spe
55
131 146 209 229
Name Item Nature

Double Powder

Leftovers / Lum Berry Modest
Moveset EVs
~ Sleep Powder
~ Stun Spore
~ Explosion
~ SolarBeam
96 HP / 252 SpA / 96 SpD / 60 Spe

Only, and I mean ONLY use this set on a team containing Groudon. Drought will automatically trigger Chlorophyll and remove SolarBeam's charge up turn. Exeggutor is an excellent counter to an enemy Groudon, as long as it doesn't use Hidden Power Bug or a Fire move. SolarBeam is an easy OHKO on it, but don't use it too soon—you will swiftly be met by Kyogre, Rayquaza or some other Uber that walls you, so catch one with Sleep Powder, then paralyze the next with Stun Spore. Unless the sun is shining, Exeggutor is quite useless in Uber battles because almost everything but Groudon walls it, so don't be afraid to Explode. Psychic is not on this set because a lot of things resist it.

Name Item Nature

SubSeed

Leftovers Modest
Moveset EVs
~ Substitute
~ SolarBeam
~ Leech Seed
~ Explosion / Sleep Powder
124 HP / 188 SpA / 96 SpD / 96 Spe

With Chlorophyll, Exeggutor outspeeds just about everything and can perform Sceptile's SubSeed technique quite well. Leech Seed your opponent, and keep using Substitute to drain its health down. This is very useful to drain Blissey's health and support the rest of the team.

Other Options

Hidden Power Dark has been used in the Uber metagame for a while, but a lot of things still take nearly no damage from it as Ubers tend to have high Special Defense (Latios, Latias, and Kyogre, for example). Hidden Power Ice can be used in Ubers to hit Rayquaza. Wish is useful in any metagame.