Ok is this normal?

background: we placed frank in new terrarium (exo terra 90cm x 45cm x 45cm) last week and hes been exploring it for a few days now. Frank has been eating very well 26-29c and 31-34c (thermostat and two hea. temps are within caresheet and i have 2 hides. humidity is about 50-60.

terrarium:
http://www.flickr.com/photos/5051687...8334/lightbox/

today i saw a weird muscle twitching. its hard to explain but i link a video here.
http://www.youtube.com/watch?v=c7uAvAR_vSA

sorry for bad video and english. But my python looks like hes from alien movie and someone is trying to come through hes stomach!