Zombie head
Summer prize token was removed from RuneScape after an update, but still exists in-game for those who had obtained it.
Summer prize token detail

The summer prize token was a possible reward from opening a mystery box, obtainable during the Summer Beach Party from 25 June to 28 June 2015 from either the Summer Raffle Treasure Hunter promotion or from Reyna before the commencement of the 2015 Summer Beach Party.

The rewards which you can choose from are:

Summer prize token interface

The interface for redeeming rewards

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