Use one of the following values with the "spawn [object name]" code:

char_doctor
char_kane_strogg
char_marine
char_marine_fatigues
char_marine_medic
char_marine_tech_armed
monster_berserker
monster_bossbuddy
monster_failed_transfer
monster_fatty
monster_gladiator
monster_grunt
monster_gunner
monster_harvester_combat
monster_iron_maiden
monster_makron
monster_network_guardian
monster_repair_bot
monster_scientist
monster_sentry
monster_slimy_transfer