bag of Lego

As an action, you can spread a bag of Lego to cover a square area that is 5 feet on a side. Any creature that enters the area must succeed on a DC 18 Dexterity saving throw or stop moving this turn and take 2D12 piercing/ bludgeoning damage. Taking this damage reduces the creature's walking speed by 10 feet until the creature regains at least 1 hit point.

alternatively you can make a truck.