Power Surge's EMP?

When Surge wear[s] off and triggers the EMP, is the Hold the only effect that targets critters or is there an endurance drain component [for the critter] as well?

According to city of data, power surge summons this pet when it expires. It's listed as doing 22.35s of mag 3 hold with a 50% chance for an extra mag 1, -55% endurance, -1000% regen for 15 seconds, and a minor energy damage component to robots. Note, though, that it doesn't have any -recovery, so even if it drains something they'll start gaining it back immediately. Also note that the power isn't autohit and has standard accuracy, so you'll probably want to slot some acc in it if you want to be able to rely on that effect.

I have my skill 5-socketed with Unbreakable Constraint for the purple bonuses. The hold is great when you crash and a surprisingly awesome feature on this skill. The endurance drain does take effect but is not worth augmenting through sockets-- the lack of a recovery debuff means that a floored foe will be attacking again after a second or two.