An Easter egg is an intentional inside joke, hidden message, or feature in an interactive work such as a computer program, video game or DVD menu screen. The name has been said to evoke the idea of a traditional Easter egg hunt.
“A special level accessed by collecting four Prime Evil Artifact and talking to Um in the Town of...Fallen Inoya
“Sheeponia reference to Diablo 2 "Secret Cowlevel". Sheeponia Boss spawns in a small enclosure...Easter Eggs