Shapechanger: Imp can use it's action to polymorph into a beast form that resembles (speed 20ft), a raven ( speed 20ft fly 60ft), or a spider (speed 20 ft, climb 20ft. Or back to it's true form. It's statistics are the same in each form except for the speed changes noted. Any equipment it is wearing does not turn invisible. It reverts to it's true form if it dies.   Devil's Sight. - Magical darkness doesn't impede the imps darkvision.   Magical Resistance. - The imp has advantage on saving throws against spells and other magical effects.