A BFGsound

A_BFGsound is a code pointer used in the attack animation for the BFG 9000.

just plays the DSBFG sound effect (the BFG's long "warm up and fire" sound effect). The sound origin is the player firing the weapon.

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 = 84

Or using BEX syntax:

[CODEPTR] Frame 1234 = BFGsound