The trinket of sealification is used in the 2010 Christmas event to turn the player into a seal. The player would use this to turn into a seal and complete a specific part of the 2010 Christmas event. By picking up the trinket, it is automatically stored in Thorvar's bag. Upon using the trinket, the player will obtain the Seal of Approval emote. The trinket looks like a seal balancing a ball on its nose.
During the 2016 Christmas event, when the player tries to use the trinket, it disappears into the depths of the bag and respawns behind the player before being used for its intended purpose.