Time Sap

School: Chronomancy (Transmutation)
(Intended for use with a Chronomancer subclass such as the School of Temporal Magic)

Bluish-grey mist from the Demiplane of Time wreaths your hand absorbing some of the timeline of a creature you try to touch. Make a melee spell attack against the target. On a hit, the target takes 1d4 force damage and it can't take reactions till the start of it's next turn. Also, it's speed is reduced by 5 feet (up to the creatures maximum speed) and your speed increases by the amount reduced till the start of your next turn.

This spell's damage increases by 1d4 and the speed effects increase by 5 when you reach 5th level (2d4 and 10 feet), 11th level (3d4 and 15 feet), and 17th level (4d4 and 20 feet).