Bill Murray in Zombieland (2009)
Before he got sick, the first choice of producers for the celebrity cameo in the horror comedy Zombieland was the late Patrick Swayze. Matthew McConaughey came close but backed out at the last minute. So it was left to co-star Woody Harrelson to suggest his Kingpin co-star Bill Murray. Murray liked the script but wanted more to do. (Originally he was meant to be a zombie with no lines.) So the part was rewritten so that his character was alive and wearing zombie makeup to blend in with the undead hordes who have taken over the country.