my baby beardies!

Question
We own four baby bearded dragons, and yesterday we found one of them not able to move on the bottom of the cage with his back legs and tail paralyzed. He has and unusually large bump right on the beginning of his tail by his back. He will start to twitch, shake and go completely stiff from time to time. DO you have any suggestions on what this could be from????

Answer
 I would take the baby to a a good reptile vet as soon as possible.  Swellings can be due to infection, trauma, or some other underlying medical issue that can be only diagnosed and treated definitively by a veterinarian.  If I had to guess, I would say that this baby was picked on by the others, so everyone should be separated.