Is it normal to have random urges to bite random things

i once ate a part of my rubber... it tasted chemical.

when im stressed i somethimes want to do anything simpel,senseless to somehow change the situation or so..

Me too! As long as it's edible, but I still bite people's arms at random. One of my friends does it too and punces upon his friends and if it's me he'll probably bite. Normal. Either that or the three of us aren't lol.

http://www.youtube.com/watch?v=w8jnqQoZ1Mw

Lol accepts a shoe in your face

I think the only way to find out if you're normal is do it.
Next time you're waiting for a train or stuck in a queue in a shop just pounce at the nearest shoes next to you and nibble away! I am sure nothing bad will happen what so ever...