Does nothing if the calling actor has no valid target. If the calling actor has a non-null special1 field, it is put in its See state.
Otherwise, calls A_FaceTarget, plays the sound "weapons/bfgf" on the WEAPON channel, and sets the calling actor's pain chance to 0 so that the firing sequence will not be interrupted. This replicates BFG9000 charging sequence.
This codepointer is restricted to ScriptedMarine and derived classes.