What happens to your hide check while stunned?

[LordotheMorning]

If you are hiding, as in you've already rolled your hide check, and then in a later round you receive the stunned condition. Are you then revealed to your enemy?

What about if you are using Hide in Plain Sight in magical darkness?

[Duke of Urrel]

I don't think your Hide check score changes just because something stuns you. However, dropping everything you're holding (if you have the bad luck to be holding things at the time you're stunned) will probably attract attention by making noise. This will probably enable every creature to estimate your location, and every creature that makes a Listen check 20 higher than necessary will pinpoint your location, even if you remain completely hidden from sight.

If a creature that hears you drop what you're holding moves until you have neither cover nor concealment from that creature, and if you can't move to make a new Hide check because you're still stunned, then that creature will automatically spot you. Of course, this won't happen if you overcome your stunned condition quickly enough. In this case, you can move to keep your cover or concealment and make another Hide check.

Magical Darkness works like any other concealment, except [WARNING: House Rules to Follow] that I require it to be at least as dark as the surroundings of all potential spotters in order to count as concealment at all. In other words, you can't hide in magical Darkness from creatures that are surrounded by even dimmer light (such as starlight, starshadow, or total darkness), but you can hide in magical Darkness from creatures that are surrounded by torchlight, moonlight, shadowy illumination, or the effect of the magical Darkness itself. This is my own house rule, and it has one house exception: Creatures with Darkvision find magical darkness within range of their extraordinary sense to be darker than total darkness, so that you can always hide from them inside magical Darkness, provided that you are within rather than outside the range of their Darkvision. [House Rules End Here.]

Being able to hide in plain sight, by itself, doesn't make you any less likely to give away your position when you're stunned. It only makes it easier to hide again after you've been spotted.

[Curmudgeon]

Yes, you become apparent when you're stunned. Hide in an opposed check. If you become incapable of making that check (to reflect different viewing angles, & c.) each round, you're no longer using the skill to oppose any observers' Spot checks.