Compression.

The boneless can move through any opening at least 1 inch wide without squeezing. It can also squeeze to fit into a space that a Tiny creature could fit in.

Unusual Nature.

The boneless doesn't require sleep.

Actions

Multiattack.

The boneless makes two Slam attacks. If both attacks hit a Large or smaller creature, the creature is grappled (escape DC 13), and the boneless can use Crushing Embrace.

Slam.

Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) 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 is unable to breathe. The target must succeed on a DC 13 Strength saving throw at the start of each of the boneless' turns or take 5 (1d4 + 3) bludgeoning damage. If something moves the target, the boneless moves with it. The boneless can detach itself by spending 5 feet of its movement. 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 13 Strength check. When the boneless dies, it detaches from any creature it is attached to.

Boneless