Keyword counter

A Keyword counter is a counter that give a permanent they're on a keyword ability. The game mechanic was featured in Ikoria: Lair of Behemoths.

Description
A permanent with a keyword counter on it gains that keyword. To determine how this interacts with continuous effects, use the counter's timestamp. The timestamp of a counter is the most recent time that any counter of that kind was put onto that permanent.

For this group of counters, having more than one of the same counter provides no additional benefit. Note that if these counters end up on a noncreature permanent, it won't necessarily apply right away, but it will if the permanent becomes a creature. (The exceptions here are hexproof, indestructible, deathtouch, and lifelink, which work even if they end up on a noncreature permanent. Deathtouch and lifelink only matter if that noncreature permanent can deal damage somehow.)

During its introduction in Ikoria: Lair of Behemoths, there were several spells that rewarded creatures with particular keywords (keyword "lords"), as well as multiple creatures and spells that granted the choice of several keywords.

History
The Chimeras from Visions were the first cards to (kind of) use keyword counters. If R&D remade them today, they would definitely use keyword counters.

Keyword counters were introduced on a test card in the Mystery Booster set (Recycla-bird with flying counters).

Ikoria: Lair of Behemoths and Commander 2020 widely expanded on this with ten more keyword counters. Double strike and indestructible counters only appear on cards in the Ikoria Commander set, and not in the main set.

With the Kaldheim Ascendant Spirit (which featured a Flying Counter as mechanic), Keyword Counters slowly moved to deciduous status. The same is true for Tyrite Sanctum (which featured an Indestructible Counter as mechanic)

Types of keyword counters

 * Deathtouch counter
 * Double strike counter
 * First strike counter
 * Flying counter
 * Hexproof counter
 * Indestructible counter
 * Lifelink counter
 * Menace counter
 * Reach counter
 * Trample counter
 * Vigilance counter

Rules
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Rulings

 * A permanent with a keyword counter on it has that keyword.
 * For determining the interaction of continuous effects, the timestamp of a keyword counter on an object is the most recent time that any counter of that kind was put on that object. Removing a keyword counter doesn't change the timestamp of any remaining counters.
 * Among the keywords that a keyword counter can grant, multiple instances of any one of these keywords are redundant.
 * Some Ikoria packs include a punch-out card with counters that appear in the set. These aren't required for play. As with other counters, players may use any mutually agreeable method to represent the counters.