I haven't had a chance to play it yet, but a couple of things springs to mind that I've been pondering.
Stun: Seems a little 'underpowered', compared to Entangle. The effect only lasts 1 turn and the target is still able to take a Move or Special action. At a read through I'm thinking of having the effect last for a number of Turns that you win the Psyche roll by. Or maybe I've missed something.
I'm trying to settle on something that would simulate Scarecrow's gas, but so far I'm not sure what would fit the bill