Bloody Nora.
I'd have put it in a giant petri dish and fed it, clapping the lid down sharply afterwards.
But to be serious for a moment, I'd be concerned about diverticulitis. Too big for the contents of a pocket by the sound of it but it really does sound as though something was introduced into the bowl that couldn't have arrived without you noticing. I hope!
If you have the slightest tendency towards hypochondria DO NOT Google Man with giant colon.