Normally when cats bite or scratch, they simply raw blood and create scar tissue that’s a reminder how much you really love your cats. However for a man in Toronto, a cat bite turned fatal.

The bacteria¬†Pasteurella multocida, which lives in many pets’ mouths, caused a 4-inch-wide aneurysm in the abdominal section of the man’s aorta (the large vessel descending from the heart to the abdomen) that ultimately ruptured. Six weeks after being bitten by a cat, the man died.

The lesson is that cats’ mouths contain bacteria and getting any bacteria into an open wound can be dangerous. The other lesson is that cats can be deadlier than you might think, so think twice before trying to pet a strange cat that doesn’t know you.

To read more about the man who died from a cat bite, click here.