A phantom watchdog appears at a point you choose on the ground (8 hours). The hound is invisible and remains stationary. It has Darkvision 60 ft and Perception +8. It barks if creatures approach within 30 ft, waking you if asleep. When a creature moves within 5 ft, it can bite once per turn: +10 to hit, 4d8 Piercing damage. It disappears if you move more than 100 ft from it.

Material: a tiny silver whistle, a piece of bone, and a thread