In Super Mario Bros. there are ghosts. You look at the ghosts, they don't move.
This Call of Duty. Black Ops 3 easter egg is like that. Only actually terrifying!
This could only come from the great laboratory of death known as free-for-all in a multiplayer shooter. Given enough matches, enough combatants and enough button-spamming, you'll inevitably discover that a bouncing betty to the face is a one-hit kill Call of Duty. Black Ops II -- without detonating.