Taunting
When marines kill a very powerful enemy target NPC, such as a Cyberdemon, or an enemy player, they (By default) have a 1/4 chance to play a taunt animation. If they managed to kill their powerful target by meleeing them to death, they will be twice as likely to taunt. If there is still danger around however, they will not risk taunting their dead enemy. Marines will also stop taunting if a threat appears.
The chance of them doing a taunt can be controlled with the User_TauntChance variable.
Marines have the following taunts:
Just 2 generic rifle wave animations followed by a taunt sound. They will randomly wave their rifle 2-5 times before stopping.
If the marine randomly picks this taunt, they'll play it for about 4-6 seconds before stopping.
Special taunt which is only activated if the dead enemy isn't too far or unreachable. Makes the marine walk up to said enemy and teabag them 5-15 times before stopping.