so i was going 80 through town yesterday...

Easy, you have a non sure grip rear and you are hydroplaning the right rear tire. If you take a non suregrip car and put it on jackstands, put in in drive and take the speedo to say 40mph, if you were to put 1 tire to the ground and stop it, the other one will shoot up to 80mph. Something of that nature must be happening to you.