If you could have a Champion Guest star in an Anime of your choice, who and what would it be?

I don't watch much Anime but here goes

Berserk for obvious reasons.

For some reason i'm thinking that seeing her in a Naruto episode would be cool, not sure why.

Edit: RWBY no doubt in my mind that would not be the coolest thing ever. In that show people all have a weapon that turns into a gun, she turns into a dragon which is like a living flamethrower.

And if you want Anime's based around Video Games work too.