What?

When I got home today, I saw evidence of something chewed up by the dog.  But what is it?  It's rubbery and something that was a sphere or half of a sphere.  This picture taken by my phone, not in very good focus.  The inside is brown and th outside seems to have some whice highlights.  Maybe a blue rim across the top.

When  figure it out, I'll probably be really mad.  But I don't know (neither does Dennis) what it is?