As he drinks the contents of this small vial. Zenotas implodes, causing a sinkhole. As he sinkhole forms; tentacles, tendrils, jagged shark teeth, 1000s of scavenging crustaceans and water explodes from the center creating this 5ft hole going down into abyss; expanding to 30ft as the Puddle gets larger. The water is shallow and rapidly spreads up to 200ft diameter around corners and cover; by seeping under it and through it. As the puddle reaches its limit, it pulls creatures and anything else into the Maw, if a creature is in an inanimate object, a house for example. The creature needs to make a DEX save to get out. 

Creatures in the water or starting their turn in water must make a STR save, or be pulled 30ft towards to Maw and are considered grappled. Small and tiny creatures automatically fail, Medium gets do with disadvantage. Large and huge roll as normal. Those he considers as family/friendlies, seen before he implodes make the save with advantage plus his twice his CHA modifier. Apart from family/friendlies. if creatures still in the water need make another save or be grapple and pulled 30ft. If a creature is pulled into the Maw, they take 10d12 bludgeoning damage until they escape the Maw. Those that succeed the throw cannot move away from the center but only perpendicular aligned with center

The 200ft of water is considered difficult terrain and is linked to interdimensional space; which make it unable to teleport away from. If any body of water is nearby, the range increases.

Can be done once every 4 days, he does it again before that cooldown period, he will suffer 4 levels of exhaustion