One of the tiny toy hats that used to hang in Phoenix's house, before she chewed through the string holding it up. (She nibbled it a bit, but preferred to chew the little beads that were on the string!).
Thanks for playing along with yesterday's guessing game. Yesterday's pic was, as @nicolecampbell and @kchuk guessed, bubble wrap! (A few others guessed bubble wrap too, but among a number of other ideas!).