187

187 refers to destroying a creature or other permanents using a "comes into play" effect, such as when the card Nekrataal comes into play; by extension, "187 effects" are effects which trigger when creatures come into play. A common yet wrong assumption is that the term originated from Nekrataal's collector's number in the Visions set (which has only 167 cards). Another misconception is that this expression comes from the section of the comprehensive rule book that dealt with 'comes into play' effects.

In reality 187 is derived from the California penal code for murder.