That would be beyond based for a mega. Or give it arena trap or some shit. Maybe shell smash too.
Torterra was my first starter. Leech seed was my favorite move, stealing 1/8 of their hp each turn is actually a lot and it synergizes well with wood hammer. Also helps with catching Pokémon you outlevel. Stab earthquake also wrecks so many mons. Stone edge for coverage. Gyarados goes well with torterra, torterra protects him from electric moves, gyarados bounce helps stall leech seed, plus intimidate. Staraptor also was on the team with intimidate and fly to stall leech seed. Strong fighting type like Lucario, Machamp, or Gallade helps deal with ice types. I hope the 3D models in future games look better, I miss the sprites.