Draffyn's Necrotic Windfall

The caster takes 1d4 of damage from extracting the blood and summons 3 clusters of plague rats, which can be split and directed to targets in range to attack.

A target must make a constitution saving throw or take 1d6 necrotic damage per cluster on a failed save, or half as much damage on a successful one.

If the target fails their constitution saving throw and has enough clusters attacking them for their size (see below), they have disadvantage on all attacks until the start of the casters next turn.

The caster can use their action on their next turn to continue channeling the spell and redistribute the plague rat stacks.

Number of clusters needed to have a chance of applying disadvantage:

Tiny: 1

Small/Medium: 2

Large: 4

Huge: 6