Not a Gray expert, bur since the species is so prolific, I have never heard of captive bred Grays, so I am assuming this one was wild caught. Looks like possible fly / wasp larvae infestation? That, and the paralyzed state indicates nervous system compromise. Animal should be removed and quarantined. When eggs erupt, the maggots will consume the frog. Sorry, 100% fatal. Wasp poisons are designed to paralyze all but the minimum respiratory functions so the embedded larvae develop in peace.