That makes sense. I can see that
It is actually I nymphalis antiopa!
I looked at where you were from and then looked for caterpillars and butterlies native to the area. That's the one I found that looked as close as I could tell from the picture
I tried google searching via "Prickly Caterpillar" alas, being tired I couldn't figure it out. Normally I can weed through info so well and gather up the important details that I'm searching for based off of how I choose to type in my wacky key words.. I'd be very interested to know what you find out.
Did it have a red stripe down it's back? Looks like aGulf Fritillary Caterpillar. It'll turn into achrysalis butterfly