Bellsprout, the Flower Pokemon

Bellsprout is a weird little guy. But put him in the sun, and he'll bloom into a powerful fighter!

Synthesis
Weather Ball
Solarbeam
Growth/Sunny Day/Stockpile/Leaf Blade

IVs: 31 HP, 31 Sp. Attack, 31 Speed
EVs: 252 Sp. Attack, 128 HP, 128 Speed

I couldn't quite determine what direction I wanted to go in with this guy, other than putting him in a Sunny Day team. Synthesis heals 2/3 HP in sunny weather. Weather Ball becomes a Fire-type attack with 150 power in the sun. Solarbeam will have no charge time in the sun, and also gets a STAB, so it will have 180 power. Victreebel's Ability is Chlorophyll, so his Speed doubles in the sun(from a base stat of 70 to 140). The 4th move is up to you, depending on your style of play. Growth raises your Attack and Sp. Attack stat one stage each, 2 stages each if it's in the sun. Sunny Day would set up the sunny weather(use this if you don't have someone else using it). Stockpile raises your Defense and Sp. Defense one stage each(no weather effect, just if you want better defenses). Leaf Blade would be a good STAB physical attack to have to compliment the special attacks in this set.

How to get him?

1) Breed a male Roserade that knows Weather Ball and Synthesis with a female Bellsprout.
2) Aim for a Nature that lowers Attack(unless you're going for Leaf Blade as that 4th move, then go for a Defense or Sp. Defense lowering Nature).

Have him hold a Focus Sash so he can get an extra turn, and voila, a vicious plant to mess up your opponent's plans! Questions and comments are welcome.

Brock out.