So if one rolled SIPHON on the same char as rolling PHYSICAL DISABILITY.
Could you take a -15 Unable to walk disability, and then make Siphon ranged, and reversible could you transfer your disability to a target, effectively making them real slow (assuming they can't fly) and then be able to get up and walk while your weakness has been transferred?
Asking for a friend ;o)
While the effect certainly seems like a very cool effect I think that Siphon is not the right ability for that. If you make it reversible the effect would be - to my mind - that you transfer hitpoints, power points or ability points to your target. There is no statement about weaknesses and I think this is okay. Otherwise you could have Zombies with zombifying rays ... Okay that would be an awesome enemy, but ... back to my original point ;-D
There are already abilities with the necessary effects so you don't need to take siphon and twist it with an array of modifiers. You could take Heightened Agility or Speed and reverse it to slow down your target or take paralysis ray. As a GM I would also allow you to take a special modifier on paralysis ray so that it only affects your legs.
I agree with Curse.
-Jeff
Lots of ways you could do this. Maybe Link Transmutation (which allows you to give people weaknesses) and Speed, so you can only move after you've hobbled someone?