Unfinished Doom 3 monsters
Several Doom 3 monsters were cut in the design process and did not make it into the finished game. Various concept designs of these monsters were shown amongst the pre-release Doom 3 promo material. One of them was a new version of the Arachnotron while the rest were apparently new designs. Eventually some of the unfinished monsters were finished and used in the Doom 3 expansion, Resurrection of Evil.