>>85143569the biggest thing I remember Beast Boy turning into was, well, Godzilla back in one of the early issues of New Teen Titans. Washername was attacking the Tower with her magnetic powers and he was blocking incoming debris, swatting cars out of the air with his tail.
Then a cruise liner hit him in the face and took him out.
I dunno how long he could have held that form, or if he truly was as strong as a form that size should be or if he was largely "hollow". But Godzilla doesn't exist in the DCU so the implication is that he turned into a creature he saw from a monster movie, he wasn't limited to "real" animals.
So can he turn into whatever he can imagine?
Another point of reference, during the Titans/X-men crossover, his turning into Lockheed the Dragon, the *big* one from Kitty's fairy tale story before she got the miniature pet after Claremont fell in love with the idea. Non-canon, though.