The Midnight Grazer

Late one night, a young man was abruptly awoken by a violent argument from the house next door. The screaming soon escalated into the shattering of glass, followed by the heavy, sickening thuds of an axe. Then, an eerie silence fell, broken only by a bizarre, rhythmic tearing noise from the lawn outside—it sounded exactly like a large beast grazing on the wet grass. A few minutes later, there was a series of weak, wet thumps against his front door. Assuming it was a stray animal or a neighborhood prank, he rolled over and went back to sleep. The next morning, he opened his door to find his neighbor's wife dead on his porch. What exactly happened?