I assume you want to span another when this unit dies much like the Spawn Broodling behaviour for Zerg buildings?
They work by using a Create Unit effect tied to the Death Response property of a Behaviour (located under the Combat tab in the Behaviour: Modification + property). Take a look at the Zerg Building Dies 6 and Zerg Building Dies 9 behaviours as an example. Post back if you need further assistance.
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory