I must not have made myself clear, as two people have misunderstood the effects of my ability now.
Steps:
1: You Cast The Area Of Effect Spell
2: Loop the following statement (lets say 10 times)
Damage all units in the area based on how long THAT INDIVIDUAL UNIT has stayed in the area for (leaving the area will reset the damage amount)
Wait 1 second
I have an idea though, what I'm going to do is add dummy abilities to the units, with the dummy ability having levels equal to the duration of the damage over time spell (in seconds), every second each unit in the region has the level of it's dummy ability incremented by 1, as well, units in the whole map with the DUMMY ABILITY that are outside of the region have their dummy abilities removed. I'ma get to work on this right now.
P.S. While I'm posting, does anyone know why this trigger action doesn't move a preset region?:
Region - Center Bore Tunnel Wyrm <gen> on TempPoint
If this doesn't move a region, then what action does?
Or at least, it wouldn't be worth the time to try and make it. It would be possible, but it would not be fun. Question, though: why can't you use custom values?
P.S.S. I can't use custom values becomes I'm using them somewhere else XD.