Menace

Menace is a static ability that makes a creature unblockable unless it is blocked by more than one blocking creature.

Comprehensive Rules
702.110. Menace

702.110a Menace is an evasion ability.

702.110b A creature with menace can’t be blocked except by two or more creatures. (See rule 509, “Declare Blockers Step.”)

702.110c Multiple instances of menace on the same creature are redundant.