Well, the reason I left the powers category undefined is that I'm not sure how powers are defined in the campaign I'm thinking of joining. I considered the power as a sort of 'schadenfreude': the guy watches someone try to do something fancy and makes them screw up. I figure it's a mental power, BOECV, and might, with living beings at least, have the 'Works against EGO, not BODY' enhancement-- perhaps he's unconsciously creating mental static.
It's possible that that this could be worked out as a Multipower, so that it has the 'Works Against EGO' enhancement for the slot that whammies living beings' powers but not for the one whammying foci.
I *am* thinking it'd probably be an All or Nothing transform, and that it does wear off after a relatively short period of time, so healing would be defined as some fast rate like maybe REC's worth of BODY per turn instead of per month.
Another interesting jinx power I'd thought of, which doesn't affect Powers, is a Multipower Change Environment, 1 hex, -5 to STR/INT/DEX/PRE (and appropriate rolls) depending on which slot is activated....
I figure whatever jinxes I do will probably also be Invisible to Sight/Hearing (but visual to Mental Senses as if they were regular mental powers), and maybe requiring Concentration or having entertaining Side Effects (like backfiring to reduce his rolls or giving him several dice of Unluck).