This monster is present in Afraid of Monsters: DC as an edited HL1 Bullsquid, and it is a twitcher walking on it's arms with his legs twisted upwards as if appearing broken, not surprisingly it shoots white venom at the player, altough it doesn't do anythin
Poison twitcher

The infamous Twitcher reworked from a default HL1 Bullsquid.

g more than functioning as a projectile if it were fired by anyone else, dealing long range and melee damage should it get close enough, it will perform a sort of tackling attack while dealing moderate to high damage depending on the difficult level. It's not necessarily poisonous but appears to shoot some kind of poison from it's mouth.