A_Summon

If the summoned monster cannot be successfully spawned in its location, or if the calling actor does not have a valid tracer, it is instantly removed and a new ArtiDarkServant is spawned in its place.

A_Summon
(no parameters)

Spawns a MinotaurFriend.

Otherwise, the summoned monster has its StartTime field set to the current tic, its tracer field set to the summoner (unless the summoner is dead), the summoner (if alive) is given a PowerMinotaur, the summoned monster's friendliness setting is set up, a MinotaurSmoke is spawned and the summoned monster is made to play its active sound on the VOICE channel.

This codepointer assumes that the summoner is the actor stored in its tracer field and it is restricted to SummoningDoll and derived classes.