The dog collar is an item exclusive to the Doom RPG. It can be used on any species of the hellhound class to capture them. The captured hound then functions as a melee weapon and is placed into the weapon selection order along with all other weapons. If the hellhound is active when the player would be damaged, the canine absorbs the damage instead, with its ammunition counter acting as its health display. When the canine's HP reaches zero, it is killed and the player can no longer use it.
- When all weapons (including any captured canine) are taken away from the player (as in Sector 3 and Sector 7), and player uses a dog collar to capture a different kind of hound, he will have both kinds when he gets his weapons back. However, their hit points are shared, and will not increase when weapons are returned.
- In a similar situation (except the type of hound does not matter), one can let the newly captured hound be killed by damage. When the player gets his weapon back, he will have a zero-hit-point dog which will pass through damage to the player, but remain usable. This is useful as medkits to heal the player are much more plentiful than dog collars.