Key

Keys were a joke item from Java Edition 3D Shareware v1.34. There are three different keys: red, yellow, and blue.

Mobs
The red key was dropped by the wither, the yellow key was dropped by ravagers, and the blue key was dropped by the elder guardian.

Trivia



 * Keys were probably inspired by The Europa Arcology Incident, a game made by Mojang in 2009 in which keys appeared, but there was a green key instead of a yellow one.
 * Another theory is Keys were inspired by DooM (1993).