False Appearance. If the scarab is motionless at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn't observed the scarab move or act, that creature must succeed on a DC 18 Intelligence (Investigation) check to discern that the scarab is animate.

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit:5 (1d4 + 3) piercing damage. If the target is a creature, it has disadvantage on attack rolls until the start of its next turn.

Scale Dust (1/Day). The scarab releases magical glittering dust from its wings. Each creature within 5 feet of the scarab must succeed on a DC 13 Dexterity saving throw or be outlined in blue light for 10 minutes. While outlined in this way, a creature sheds dim light in a 10-foot radius and can't benefit from being invisible. In addition, every Dragon within 1 mile of the creature becomes aware of it and can unerringly track the creature. Casting dispel magic on the creature ends the effect on it.