Saeviomagy
Adventurer
Arguments saying "the rules don't matter because everyone plays nice" are totally pointless - if they were true, we wouldn't be discussing the rules at all.
Arguments saying "it's limited by the creatures you have seen" in order to limit the effects of the power are pretty bad - because it requires DMs to alter their world in order to prevent the characters from seeing certain creatures, most specifically those creatures that are the most interesting, because those are the likely targets for players to turn into.
That said, I think the easiest solution is to open the MM and use the Doppleganger's shapechange ability, which lets you turn into any medium or small humanoid you have seen. The only stat change is your size.
Arguments saying "it's limited by the creatures you have seen" in order to limit the effects of the power are pretty bad - because it requires DMs to alter their world in order to prevent the characters from seeing certain creatures, most specifically those creatures that are the most interesting, because those are the likely targets for players to turn into.
That said, I think the easiest solution is to open the MM and use the Doppleganger's shapechange ability, which lets you turn into any medium or small humanoid you have seen. The only stat change is your size.