Kursed
Many fans will will know Adewale Akinnuoye-Agbaje from the show Lost, who was eventually taken out from the smoke monster. However, he played quite a different character of Algrim in Thor: Dark World who eventually turns into the monster Kurse.
Underneath all of his horns and bones as the character of Kurse, few people would have been able to know who he was if he hadn’t already appeared as Algrim, with his bleach wig and bright blue contact lenses.