Dango, Dango, Dango~

It means pervert or something right?
(hen - strange, forgot what tai was)

Correct. 変態 is usually used for pervert (it does have other meanings as well, like transforming and such); Japanese people don't use this word to refer to adult animation and comics. Yet we use this word in English, and you obviously know what it's referring to. In this case, the original meaning of this word in its original language has been lost somewhere along the lines, and the word means something different for us.

You're right, アニメ is simply "animation" in Japanese, but we have a word for that in English. So why use this word? Because we don't use it in the same way. It means something different to us (though in this case it's more related to what the word originally means).

Just like hentai, anime has spawned a meaning of its own to us.