Touch of the Gelun

You concentrate & analyse yourself, identifying your body heat and withdrawing it away from your hand. As your hand chills, you can optionally choose to pay the material cost of this spell.

Make a melee spell attack against a creature within your reach. On a hit, the target takes 2d6 cold damage. 

If the caster paid the material cost for this spell, the target has their movement speed reduced by 10 feet.

If the target's movement speed is already 0, the target gains a point of Exhaustion.

The target can make a Constitution saving throw at the end of each of their turn to end the movement speed reduction.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.