Summoning sickness

Summoning sickness is an old phrase used in the popular card game Magic: The Gathering to describe what a creature card had upon being put into play by its controller, meaning it could not attack or tap on that turn. This was also sometimes referred to as a sort of "jet lag".

If a creature had the ability to attack and tap on the turn it came into play, it was said to be "unaffected by summoning sickness". As of 1999, this has been changed to being said the creature has Haste.

Since the introduction of the word Haste into the Magic world, the phrase "summoning sickness" has been all but purged from Magic rulings. However, many older Magic player still refer to it as such, and sometimes as "the mechanic formerly known as Summoning Sickness" (see Prince). Any spells or abilities that required a creature to either have or not have summoning sickness were reworded to refer to a creature that were/were not "under a player's control that the beginning of their turn" or similar.