Unusual Nature. The defender doesn't need air, food, drink, or sleep.
Electrified Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit:7 (1d8 + 3) piercing damage plus 7 (2d6) lightning damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be grappled (escape DC 13). A creature grappled by the defender takes the damage again at the start of each of the defender's turns. The defender can have only one creature grappled in this way at a time, and the defender can't make Electrified Bite attacks while grappling.
Light Beam. The defender emits bright light from its eyes in a 60-foot cone, or it shuts off this light.
A clockwork defender is a mechanical quadruped that vaguely resembles a hound. Its eyes glow and can project intense but harmless beams of light. It tirelessly protects whatever its creator wants, and it can be programmed by its creator not to attack certain kinds of creatures.