The joke is that fan Rotom's ability is redundant. There are only two Pokemon with abilities that grant immunities that are already granted by the ability wielder's types, and fan Rotom is one of them. If you just want to win, then you have no sense of humor.Maybe I don't get it, but what is the Easter Egg behind that? Because if I have to use it in a random battle, it's no longer an easter egg to me (I just want to win lol)
By the way, we really should have Stunfisks with limber and cheri berries.