Gruesome night in the OHL on Thursday ... a goalie was cut so severely by a skate -- blood poured onto the ice and the guy needed emergency surgery to save his life.
It all went down in Canada ... where during the 2nd period of the Niagara IceDogs' game against the London Knights, a player slammed into IceDog goalie Tucker Tynan.
The collision wasn't too violent ... but after a few seconds, it became clear something was VERY wrong -- because blood began to profusely pour out of Tynan's leg.
The 17-year-old was tended to by trainers for roughly 10 minutes on the ice before he was rushed into emergency surgery. The game, meanwhile, was immediately canceled.
The IceDogs announced the surgery was serious ... but thankfully, they said Tynan pulled through and is now "stable and safe" in a local hospital.
The scene after Tynan left the ice was pretty gnarly ... you can see in a picture of the aftermath, a portion of the crease was soaked in blood.
1/3: Something you never want to see, @OHLIceDogs G Tucker Tynan appears to have been cut by a skate by a London player in the crease. He was quickly attended to by medical staff who stopped the bleeding and got him onto a stretcher.#OHLpic.twitter.com/QrE5ZqqFLq