Smiley Copy Bosses is a newer than a regular boss, but it's still fairly old.
The creator first makes a regular boss with the gravity dots on the outside, key doors that let players in, etc. However, the creator usually makes a box around it like in the picture. Then the creator makes a line of small "inescapable traps" which is the purple mineral blocks in the picture. The creator attempts to push smileys so that exactly one smiley is in each "slot". When a player goes into a round, the creator changes into the random smiley face then the other player will copy the creator that change into the random smiley face. If the player can't get the right smiley, the player either gets eliminated on the spot, or loses a "life" represented in decorations. When the player is all out of "lives" (decorations) the player is eliminated. Guests are often not allowed on Smiley Copy Bosses because guests cannot get most of the smileys. The first smiley copy boss is unknown, but the trend picked up somewhere during 2011.