The Glass Box emote used to be unlocked as a Random event reward from the Mime event. Players can now unlock this emote by purchasing a piece of mime clothing from Iffie at Thessalia's Fine Clothes in Varrock.
To complete the event, players must imitate the Mime's actions. One of the emotes that a player may be required to imitate is the Glass Box emote. When the event is complete, players will be returned to their previous location within the RuneScape world along with a random event gift where players should choose the option for unlocking an emote to unlock one of the four Mime emotes including the Glass Box emote. Players cannot choose which among the four Mime emotes to unlock as it is random which will be unlocked.