Sometimes they foil an attempted mugging.

A 52-year-old woman told officers she was walking her boyfriend’s pit bull about 6 p.m. Tuesday on the beach near 76th Avenue North when a man armed with a knife approached her and demanded her cell phone and anything else she had with her, police said.

The woman said the man wore dark clothing and a ski mask covered his face as he pointed the knife at her throat, according to the report. The woman said the pit bull became aggressive and bit at the suspect.

Sometimes they eat your heroin stash.

A man who allegedly “completely disembowled” his pet pit bull because the dog swallowed a bag of heroin has been charged with animal cruelty, according to police.

Sometimes they bite your head.

An Oshkosh woman needed stitches after a dog bit her in the head Monday afternoon.

The 18-year-old woman had been in a verbal argument with another person at her residence in the 1500 block of Hazel Street, but had gone upstairs about 2:35 p.m. A 3-year-old pit bull then ran upstairs and attacked the woman. The dog bit the woman in the head, causing two lacerations that required stitches