Unusual Nature. The boneless doesn’t require sleep.
Immutable Form. The flesh of the Boneless Colossus is bound by powerful hexes that keep it within its writhing form.
Multiattack. The boneless makes three Slam attacks. If any two attacks hit a Large or smaller creature, the creature is restrained (escape DC 20), and the boneless can use Crushing Embrace.
Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 5) bludgeoning damage.
Crushing Embrace. The boneless wraps its body around a Large or smaller creature grappled by it. While the boneless is attached, the target is blinded and restrained, and is unable to breathe. The target must succeed on a DC 20 Strength saving throw at the start of each of the boneless’ turns or take 16 (3d6 + 7) bludgeoning damage. A creature, including the target, can use its action to try to detach the boneless and force it to move into the nearest unoccupied space, doing so with a successful DC 20 Strength check. When the boneless dies, it detaches from any creature it is attached to.
The Colossus may make a reactionary grapple in the place of an opportunity attack.