TORMENT: Being a CREATURE can be painful, but you can use that pain. Spend SP up to -10, making a CON roll with each point below 0. IF you fail the roll, fall STUNNED. IF you make it, continue to fight!
Here’s how I interpret that—
So the default is: Stun Points power abilities, and they are lost alongside other incoming attacks. If a character drops to 0 Stun, they take a knee, effectively—err, Stunned and unable to act or move or use powers until they Recover.
But a Creature with Tormented can go below 0 Stun, all the way down to -10 Stun. Spending Stun to fuel powers and also when they take damage. BUT… for every Stun Point they fall below 0, they must pass a CON check or they become Stunned like anyone else already would be.
Example: Swamp Thing and some non-Creature are both at 0 Stun. The non creature is Stunned till he recovers some Stun Points. Not so ol’ Swampy. He can still move, Act and use powers. So he uses a power that costs 3 Stun Points (even though he’s in great Torment!). After using the power, he must pass 3 CON checks or become Stunned. He does, and can fight on. BUT THEN—he gets hit by something or other and takes a point of Stun along with the regular damage. He makes a CON roll for that point he just dropped below zero. If he passes, he fights on; if not, he falls Stunned. He can continue this process until he hits -10 Stun or fails a CON roll, at which point, you guessed it: He falls Stunned and must recover.
Now what may be a grey area here is: if he recovers to -8 Stun, can he A) return to rolling CON and fighting on? Or B) is he going to remain Stunned till he gets back to positive 1 point of Stun? I’m thinking I’ll probably go with (A) in my games because that sounds dramatic and Tormented AF.