Booger bomb

You rapidly stick a finger in your nose to dig for gold. A beautifull ball of respectable size emerges as you fling it at the target. Upon striking a surface the ball swells and stick. Make a ranged spell attack. On a hit a large or smaller creature has it's speed reduced to 0. A huge creature only takes a 20ft penalty to it's speed and a gargantuan creature only a 10ft penaaty. If the creature is flying and it's speed is reduced to 0 it falls but can stille use it's other speeds. On its turn a creature can use an action to break free after succeeding a strength saving throw. The booger has an ac of 15 and 15hp.