Bonereaper

Standing Leap. The Bonereaper's long jump is up to 40 feet and its high jump is up to 20 feet, with or without a running start.

Leaping Combat.  The Bonereaper has advantage on attacks made while using its Standing Leap trait.  On a successful hit, the target creature must succeed on a DC 15 Strength saving throw or be knocked prone.

Multiattack. The Bonereaper makes two scythe attacks.  If both attacks hit, the Bonereaper can attempt to pin the target.  The target creature must succeed on a DC 15 Dexterity saving throw or become grappled.

Scythe. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) slashing damage. 

Decapitation. If a target creature is prone or grappled, the Bonereaper can use its Multiattack to attempt to decapitate it.  If either scythe attack hits with a dice roll of 20, the Bonereaper cuts off the creature's head.  The creature dies if it can't survive without the lost head. A creature is immune to this effect if it is immune to slashing damage, doesn't have or need a head, has legendary actions, or the GM decides that the creature is too big for its head to be cut off in this way.  If neither dice roll is a 20, the target takes half damage from any successful hits and has advantage against the Bonereaper on its next attack action.