The experience of Underdog was apparently not enough to scare Peter Dinklage off costumed hero films or working alongside beast-like geniuses (he co-starred with Jim Belushi). Dinklage has reportedly joined the lastest X-Men film, Days of Future Past, director Bryan Singer officially confirming his involvement in a tweet yesterday. His role still isn't known--some are guessing the Alpha Flight hero Puck, because that guy is also under five feet and wears a Van Dyke pretty well--but Deadline offers that it will be "a key role." You don't waste Dinklage by stuffing him in a little dragon costume or something. This isn't Warwick Davis.
UPDATE: Variety claims the part is the "main antagonist." So whoever that ends up being.