If it leaves the graveyard before that point, it will stay in whatever zone it's in, even if it's returned to the graveyard before the ability resolves
In addition to these bans, which we'll get to in a moment, Wizards has stated they are going through a review of all cards that have been printed and will be taking action on similar cards in the future
Well, Butterfree gives you a way to heal 20 damage off of every Pokemon on your side of the field once per turn for free: its essentially a free Potion, every turn, for all of your Pokemon
It should be a 1st Edition card, have a holographic effect, be loved by collectors or have unique mistakes
They'd joke occasionally about being like Statler and Waldorf so it felt like a good choice and a nice gesture for all the great content they've given us over many years