Car revs with no gas pedal?

[ciplez]

I have a 06' Hyundai Sonata. It got stuck in the snow, so after digging out what I could it remained entrenched in ice, so I let it be today so some could melt before I tried again. I tried to back out of the parking spot it's stuck in when I got home from work and suddenly the engine was revving itself with no pressure on the gas pedal (I didn't notice if it had done this the whole time, but it seemed to start after I had tried to put in reverse and back out a few times). Now as soon as I turn it on it starts revving at about 2000 rpm's, and when I put it in reverse or drive it is trying to spin the tires.. does anyone know what's wrong/how this happened? Thanks