Menace in Magic: The Gathering is an evasion ability that was introduced as a keyword in 2015 with the Magic Origins set.
The mechanic was added as a way to replace the Intimidate ability, which was overpowered in some circumstances but useless in others, making it difficult to balance.
Creatures with Menace “can’t be blocked except by two or more creatures,” according to MTG’s comprehensive rules.
The ruling around this ability comes during the declaration of blockers. For the creature to be blocked, the opposing player must declare at least two creatures as blockers.
Once that player declares those blockers, however, it doesn’t matter if one of the blocking creatures is removed, killed, destroyed, or exiled.
By legally declaring at least two blockers, the creature with Menace becomes blocked and exchanges damage with whatever is blocking it during the damage phase that follows.
Essentially, if you want to ensure your creature with Menace isn’t blocked, you need to make sure to use any creature removal on your opponent to prevent blocks prior to the declaration of blockers.
Menace as a mechanic is on 178 cards in total, with a majority of them being Black or Red in some capacity. Black has the most Menace cards with 39 percent of all Menace cards being mono-Black. Mono-red represents nearly 35 percent of all Menace cards.
Out of all 178 cards with Menace less than four percent have no Black or Red mana cost involved.