Why can't Venusaur have Weather Ball?

Question

So, I'm playing Pokemon Showdown and I make a venusaur. Its moveset it Weather Ball, Solarbeam, HP ice, and Giga Drain (bad moveset. ik.). I go to search for a battle and it says Weather Ball is incompatible with another move. I dont get it! Solarbeam is from TM, Giga Drain from move tutor, and Hidden Power from TM.Why can't I use Weather Ball?!

Answer 1

I actually think it's more the ability rather than the move.
Weather Ball is a strictly event-obtainable move for Venusaur (As a bulbasaur), and the only legal Bulbsaur (the released one) had the ability Overgrow. So it's illegal to be running Chlrophyll + Weather Ball.

Comments

You are right.

I wanted a Chlorophyll Bulbasaur for LC with Sleep Powder and I could't search for a match.