Charlie and Spike are two kittens with myotonia congenita, otherwise known as 'fainting goat' syndrome.
At the slightest sound, the kittens respond by collapsing and falling into a rigid paralysis, which lasts about a minute before they return to normal.
This condition is very rare with cats. The kittens are able to walk, but they cannot run or jump.
Aside from this they are normal