Suggestions by @castingsinmyblood

Metallo (John Corben)

as Sam Worthington in What if this actor played

Superman (Clark Kent)

as Chris Sarandon in What if this actor played

Parasite

as Tim Blake Nelson in What if this actor played

Nero Wolfe

as Robbie Coltrane in What if this actor played

Hrothgar (Beowulf)

as Kenneth McMillan in What if this actor played

Aquaman (Arthur Curry)

as Russell Crowe in What if this actor played

Legolas

as Roddy McDowall in What if this actor played

Thunderbolt Ross

as Brian Dennehy in What if this actor played

Perry White

as George Kennedy in What if this actor played

John Ryker

as Robert Patrick in What if this actor played

Highfather/Izaya

as John Gielgud in What if this actor played

Alfred Pennyworth

as John Gielgud in What if this actor played

General Sam Lane

as Ramon Bieri in What if this actor played

Levi Ackerman

as Dane DeHaan in What if this actor played

Professor Moriarty

as Charles Dance in What if this actor played

Grendel

as Barry Dennen in What if this actor played

Smiley Bone

as Buddy Hackett in What if this actor played

Amanda Waller

as Alfre Woodard in What if this actor played

Mr. Monk's Last Case: A Monk Movie

as Movies Set in San Francisco in Oddly Specific Mount Rushmores

Toby Kebbell

as Chewbacca in Star Wars