Create Mass Undead

You throw the pot outward causing the mixture to suddenly solidify and expand, rapidly manifesting into a seemingly endless horde of stumbling dead. You create a Zombie Clot (see Van Richten's Guide to Ravenloft, pg. 255). It appears in an unoccupied space you can see within range. When the Zombie Clot drops to 0 hit points it instead transforms into three Swarm of Zombie Limbs (see Van Richten's Guide to Ravenloft, pg. 254). The Zombie Clot, or its spawning swarms turn to ash when they drop to 0 hit points or when the spell ends.

Roll initiative for the Zombie Clot (or its produced swarms), each with their own turns. When you summon it and on each of your turns thereafter, you can issue a verbal command to it (requiring no action of your part) telling it what it must do on its next turn. If you issue no command, it spends its turn attacking any creature within its movement and reach nearby that isn't you, including your allies.

At Higher Levels. When you cast this spell using a spell slot of 9th level the Zombie Clot and its spawning swarms gain improvements beyond their normal. All poison damage they would normally deal is changed to necrotic damage. Their health is doubled, they gain +3 to all attack rolls and saving throws, and when they deal damage to a target they deal an additional +1d6 necrotic damage.