Crazy domino effect after a dog peed on a neighbor’s lawn … two men came out of the home and urinated in retaliation … then a knife fight broke out, sending three people to the hospital … and it’s all on video.

It went down in Queens, NY yesterday … a guy was walking his French bulldog down the sidewalk when the pooch stopped and pissed on a patch of grass. Two men emerged and peed on the dog owner’s neighboring lawn, and then a fight broke out.

One of the guys who urinated was wielding a knife, and he stabbed two neighbors, including a 39-year-old woman, and his own father … according to police.

The stabbing victims were all taken to a hospital with non-life-threatening injuries … and the suspected stabber was arrested and charged with three counts of assault. The whole thing went down yesterday, according to FOX 5 New York.

It sounds like one of the dog owners was stabbed in the back while the other was stabbed in the hand … the suspect’s father was slashed in the arm when trying to break up the fight.