Monstrosity

Monstrosity is a keyword action introduced in Theros, where it was connected to the monster theme of the set. It is an ability that gives a power boost through a one-time payment.
==Description==
Monstrosity is defined as giving the creature the ability to become monstrous. Monstrosity is an activated ability you can activate any time you can pay for it. When it resolves, it checks whether the creature is already monstrous. If it's not, the ability puts a number of +1/+1 counters on the creature and causes the creature to become monstrous. Monstrosity skipped Born of the Gods, but reappeared in Journey into Nyx. It was reused in Commander 2015, Conspiracy: Take the Crown and Modern Horizons. It also appeared in Commander 2020, and was considered for Zendikar Rising.
The Werewolf-to-Eldrazi of Eldritch Moon use double-faced card technology to portray a similar one-way transformation, albeit without the square stat change of +1/+1 counters. The Adapt keyword from Ravnica Allegiance is a tweaked version from Monstrosity that checks for counters rather than using an invisible marker.
Monstrosity is a mechanic that gets considered by a lot of sets because it's flavorful, easy to design to, and has enough "knobs" to make balancing it manageable. However, cards in recent sets such as <c>Surge Engine</c> and <c>Mild-Mannered Librarian</c> signify that "Activate only once." is an acceptable rules phrase, which render the need for a "monstrous" designation obsolete and hence may lower its chances of returning.
==Monstrous==
Monstrous is a designation of a permanent card. Many creatures with a monstrosity ability have a triggered ability that triggers when the creature becomes monstrous. There are also some cards with monstrosity that gain abilities as long as they are monstrous.
==Rules==
==Rulings==
*Although it is not a verb, it is considered a keyword action in the Comprehensive Rules.
*Once a creature becomes monstrous, it can't become monstrous again. If the creature is already monstrous when the monstrosity ability resolves, nothing happens.
*Monstrous isn't an ability that a creature has. It's just something true about that creature. If the creature stops being a creature or loses its abilities, it will continue to be monstrous.
*An ability that triggers when a creature becomes monstrous won't trigger if that creature isn't on the battlefield when its monstrosity ability resolves.
==Examples==
==See also==
*Renown, a similar mechanic from Magic Origins.
*Adapt, a tweaked version of Monstrosity.
==References==