How to put a timer on units?

I have a spell based off Parasite (from TFT). Using the TFT editor, I based a spell off it. Basically, when the unit dies, instead of a naga, it summons a custom unit, a vampire.

However, unlike the original parasite spell, my vampire unit has no timer. In other words, it will never "expire" unless someone kills it.

Is it possible to add a timer to the unit so that after it is "summoned" it disappears after, say, 120 seconds?

well what are u trying to parasite... i havent messed wit the parasite spell yet but.. does it take away health.. anyways.. in the editor it should have like:
Hero Duration ----
Normal Duration -----

just change to how many seconds u want the spell to last in that field

Events
A unit enters region (playable map area)

Conditions
Unit-type of (Entering Unit) Equal To Vampire

Actions
Add 120 second generic expiration timer to (Entering Unit)

Thanks man! Your solution worked like a charm.

Believe it not, the Stats- Casting time is acutally the TIMER FOR THE PARASITE, im sure of this. (I'll go add this to known bugs list)

Hey... it works! But now, instead of "Timed Life" it says "Parasite" in the timer bar... darn.. oh well.. I guess I'll use the trigger instead.

Isnt there a proper name field? Or maybe edit something in the spell....