Zombie head
Party hat fragment was removed from RuneScape after an update, but still exists in-game for those who had obtained it.
[FAQ] • [doc]
Party hat fragment detail

Party hat fragments are fragments with which players can assemble the 15th Anniversary party hat. 100 fragments are needed to create the party hat. Ten fragments can be obtained by opening Party Pete's 15th anniversary party box. You can obtain more by busting balloons which are dropped every half hour around all of the lodestones with the exception of Prifddinas.