The fly, sometimes thought to be a moth, was a passive, decorative creature that was originally intended to be in Hexen but was cut before the final release.
Appearance and behaviour
The fly harmlessly flutters around the portal room in the beta and the Saturn version, whereas in the PS1 version it may get out of this room and wander about the larger area before it.
Four sprites exist of the fly in the beta IWAD with the sprite name of AFLY. In the final Hexen IWAD, the only remnant of the fly left is a sound definition in the SNDINFO lump. No evidence of the fly has been found in the released Hexen source code, but restoration efforts on the 4-level beta have reconstructed its original behavior.