Hey everyone!

I was practicing basic chords for the first time on my friend's electric guitar, and the second string from the top (I think it's the A string) seemed to pop out from the bridge. However, after looking a little more closely, I saw that the string wasn't disconnected from the bridge, but it looked like it unwound. The part of the string still connected to the bridge was thinner and spiraled.

I don't really know anything about guitars, and this is my first time ever practicing with one. It's a little disconcerting that I might have already broken it! Could someone please explain what actually happened with the string? I'm not sure if it needs to be replaced or why it stretched out.

I took a few photos of the string since I thought that might be helpful.

the winding has simply come loose, string will do that after a while, don't feel bad about it, eventually even the greatest set of strings will deteriorate.
The core of the string broke and has stretched out the winding because of the tension. Time for a new set of strings.
Ibanez Prestige RG852MPB
Ibanez Prestige RG652KFX
Schecter Loomis NT
EVH 5150 III 50
PRS 212 DB
Line 6 POD HD500X
Deadhorse OD/Boss HM-2
Thank you both for the information! I'll go ahead and order some new strings.