Those nightmares are summoned by the acolythes of insanity. They normally fight anything that moves and also support other insane troops like the WeirdCorps and the Uniques. Put the MSConfigs folder in your MonsterSpawn lists backup. For team enemy support start in that team and change then.
USUAL BRAINBAG SUMMON: brainbag.BrainBag TEAM BRAINBAG SUMMON:
Also incuded the MonsterSpawn mod plus predefined brainbag configs for all teams.
And the AQueen model which is also required since the package provides the Unique playerclasses.