User blog comment:Energy X/FOB - Kanto Round 1/@comment-4275989-20141207153125

Yes, I voted for Gastly, as many as you did. But I didn't consider anything about Mega Evolution and a pure Grass-type Pokémon or such. Easy. Gastly resists Oddish's Grass-type moves, and also greatly resists Oddish's Poison-type moves (their two primal types). While, Oddish doesn't have any weakness to Gastly's moves, it doesn't resist their primal type moves' types.

Remember it was Gastly vs. Oddish, not Mega Gengar vs. Bellossom.