Pain-stun

Pain stunning is a type of gameplay exploitation that involves keeping a single monster stuck in its pain state by attacking it with a weapon with a high rate of fire, such as a Chainsaw or Plasma Gun. Using the chaingun on monsters that are vulnerable to pain-stunning is at times referred to in the Doom community as making a monster do "The Chaingun Cha-Cha." To put it simply, if a monster is spending more time responding to getting shot, it is spending less time retaliating against the player. Chaingun Guys and Arachnatrons are very deadly foes to other monsters when infighting for this reason, and pain stunning is often exploited in the final battle with the Spider Mastermind in Doom E3M8: Dis, as it is highly likely that the player is carrying a Plasma Gun from the previous level.