Expression:

In the vain of ALL YOUR BASE ARE BELONG TO US, this obscure pop-culture ejaculation finds its origin in the now notorious NES platformer Bible Adventures. A quirk of the game's mechanics enabled the player, otherwise entrusted with the safe conveyance of the baby Moses across the Nile, to commit a most heinous act of infanticide by tossing the little fellow in the drink. The player would then be admonished at the conclusion of the mission that he or she had "forgotten baby Moses" - no doubt to the delight of the thousands of disgruntled children inclined to such acts of violence by being forced to play Bible Adventures instead of a real video game.

As an expression, its variety in use is exceeded only by its capacity to offend. Generally, however, "Drown Baby Moses" is employed referentially in comparisons with gaffes of a similar nature; in disputes over which video game gaffe is the worst, it is often invoked as a trump card.
"You think THAT'S bad? Well, I have three words for you my friend: Drown Baby Moses."
by Joshua B. Wright April 5, 2004
Get the Drown Baby Moses mug.