Sun Eater. Whenever Bàs is subjected to radiant damage, they take no damage and regains a number of hit points equal to the radiant damage dealt.
Teleport. Bàs can choose magically teleport, along with any equipment he is wearing or carrying, up to 60 feet to an unoccupied space it can see. Bàs can only do this if he has not moved yet and he cannot make use of his normal walking speed after he teleports.
Multiattack. The shambling mound makes two slam attacks. If both attacks hit a Medium or smaller target, the target is grappled (escape DC 14), and the shambling mound uses its Engulf on it.
Slam. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 13 (2d8 + 4) bludgeoning damage.
Consume. Bàs swallows a Medium or smaller creature grappled by it. The engulfed target is blinded, restrained, and unable to breathe, and it must succeed on a DC 18 Constitution saving throw at the start of each of the mound's turns or take 13 (2d8 + 4) acid damage.