Engol's Dead Leg Toxin

Inspired by a mushroom that once left his entire face numb, Engol has concocted a mixture capable of inducing this effect at a distance. The mixture is contained separately within a small grenade like device, and when the pin is removed the two chambers mix, propelling the brittle container forward, which then shatters on impact. Make a ranged spell attack against the target. On a hit, it takes 2d4 acid damage, and its speed is reduced by 10 feet until the start of your next turn as their legs turn to jelly.

The spell's damage increases by 2d4 when you reach 5th level (4d4), 11th level (6d4), and 17th level (8d4).