Mega Meganium
New Ability: Overgrow/Leaf Guard -->
Flower Gift
New Typing: Grass (Unchanged)
New Stats:
HP: 80
ATK: 82 -->
117 (+35)
DEF: 100 -->
110 (+10)
SPA: 83 -->
118 (+35)
SPD: 100 -->
120 (+20)
SPE: 80
(--)
New Moves: Solar Blade, Weather Ball, Calm Mind
Desc: I had a bit more of an ambitious spread in mind for this balanced around using Petal Blizzard as its main STAB move, but it was pointed out that Meganium is pretty likely to get Solar Blade if it appears in any upcoming games, so I figured I probably ought to bite the bullet and balance it around that anyways.
Mega Meganium hits like a
truck with Sun active thanks to Flower Gift, and has bulk enough to set up with Swords Dance even without it. It's still not particularly fast, but it's an incredibly formidable wallbreaker - notably, the attack modifier from Flower Gift cannot be Hazed, and if it's set up with SD its incredibly unsafe to switch in on, even without Sun.
If youd rather run Special with Solar Beam/Weather Ball, it now has a Special boosting option, which could be more balanced if you're boosting an ally physical attacker with Flower Gift in doubles.
TL;DR Can be a setup sweeper or a wallbreaker or bulky hard-hitting team support. Held back by the Sun turn timer and a poor main attacking type.