Pacnclown, also known as Wolfenstein 3-D Meets Pac-Man and the Demon Clowns of Death is a mod for shareware Wolfenstein, compiled by Colonel Bill. It was released on August 1, 1998.
Essentially a patch of two older sets by Bill Neisius, with whom Colonel Bill is often confused, the mod features clowns and Pac-Men along with 10 new levels. Level design is of pretty good quality, and along with the new graphics the mod is overall a fun yet challenging experience.
It is playable in SDL, not featuring any code changes.