A BrainPain

A_BrainPain is a code pointer used in the pain animation for the Big Brain.

simply plays the DSBOSPN sound effect. The sound effect has no source and thus will be heard at full volume by all players in the level.

Uses
The  code pointer appears in the following states in Doom's state table:

Example
The following is an example of how to set the  code pointer in a Dehacked file:

Pointer 21 (Frame 34) Codep Frame = 779

Or using BEX syntax:

[CODEPTR] Frame 1234 = BrainPain