As two actions, you can create a vial of liquid that looks, smells, and tastes like a healing potion or other beneficial potion. However, it is actually poison. A detect magic spell reveals its true nature.
A creature can drink the contents as an action. If a creature drinks it, it must succeed on a Fortitude saving throw or be poisoned. At the start of each of its turns while it is poisoned in this way, it takes 4d4 poison damage. At the end of each of its turns, it can repeat the saving throw.
On a successful save, the poison damage it takes on its subsequent turns decreases by 1d6. The poison ends when the damage decreases to 0.
You can increase the damage by 5d4 for each additional catalyst expended.