The petmodbeta_12312k5.zip file you have requested: Mods / Single Player / Pet Mod - 29.05kb is not available. Perhaps try browsing all files for the game Doom III and upload any files you want to share or are missing. This is the only information we could locate:
This mod lets you spawn in any monster as your 'pet' to help kill other monsters. You can command them to follow you, move to a position, or attack something. Pets can also carry a flashlight or have mounted lights to help you see in the dark.