What is this??

Here's a link you can check out:
http://marci-kids.com/rigidbodyposturing.html

Here's a thread where other members have discussed it and posted pictures:
http://www.infantrefluxdisease.com/forums/showthread.php?t=22611&highlight=sandifers

Hope that helps!

Also you could try typing sandifer's into the search function. There's seems to be some debate as to what exactly constitues sandifer's syndrome, but very basically, it's positioning/movements that a child adopts in response to the pain of reflux

I think that the above posts pretty much cover it, it can vary in severity too.

You can also google a great article- author Hassib Title: a rare underrecognized cause of pseudo seizures