The Weeping Dog

A stray dog that wanders around the outskirts of town with tears streaming from its eyes, making a sound like a human weeping.

Origin
In season 2, a stray dog eats an unnamed Leafman. After this, the dog appears ill. Several episodes later, the same dog reappears as the Weeping Dog, the implication being that the dog has been transformed in some way by consuming the Leafman.

Connection to the Maudlings
Near the end of season 1, Alex Chase follows the sound of crying out into the junkyard, thinking it's the sound of a human in trouble. When Alex sees that the sound is emanating from a dog, they freeze in terror and then disappear from the series until season 4 when it is revealed that Alex had been captured by the Maudlings and mutated. In season 2 Maudlings are seen at the Speed Stop, buying a large quantity of beef jerky. Later, they are seen leading the Weeping Dog from place to place by leaving a trail of beef jerky for it to follow. It is unclear if the Maudlings are intentionally using the Weeping Dog to lure and trap humans, or if they merely see it as an object of fascination and their run-in with Alex Chase in the junkyard was a coincidence. The Weeping Dog is never used to trap anyone after season 2, only making another brief appearance in season 3 when it sprints across the road in front of Police Officer Rosa Hernandez's car while she is in pursuit of the Sunset Killer.