Endoleech

2nd-level biomancy*

Casting Time: 1 action
Range: Touch
Components: V, S, M (a toenail lost to frostbite)
Duration: Instantaneous
Class: Druid, Sorcerer, Warlock, Wizard

You touch a creature, absorbing the energy from its body and bolstering your metabolism. Make a melee spell attack against a creature you can reach. On a hit, the target takes 5d6 cold damage and can’t take reactions until the end of its next turn. In addition, until the end of its next turn, its speed is reduced by 15 feet and your speed is increased by 15 feet.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d6 for each slot level above 2nd.

*can be replaced with evocation
Source: Heliana's Guide to Monster Hunting