Might of the Master. The following numbers increase by 1 when your proficiency bonus increases by 1: the engine's skill and saving throw bonuses (above), the bonuses to hit and damage of its slam attack, and the saving throw DC of its Oil Slick action (below).   Personal Transport. The engine can act as a mount for creatures of its size or smaller, and it counts as one size larger when determining its carrying capacity and the weight it can push, drag, or lift.   Vault. The engine's long jump is up to 20 feet and its high jump is up to 10 feet