Mark Acheson is a Canadian film and TV actor and voice artist. Acheson acted in his first feature film Skip Tracer (1977) at age 17. Since then he has accumulated over 200 professional credits. Acheson is best known for roles in Elf (2003) Watchmen, Numb, and Chronicles of Riddick. He has been in numerous TV shows including Supernatural, Motive, The X Files, and Smallville. Acheson has voiced characters of Lord Tirek from My Little Pony: Friendship is Magic, Saber Tooth from Hulk VS.