1 hit kill boss with Kruller Glaive

[dadutchdevil]

So I don't know if anyone else has had this happen or not. But I just 1 hit kill cannonbalrog with the kruller glaive. Walked into the boss room, tired to use the box item I had, obviously didn't work, the Phoenix companion I had fired a shot, and I hit Cannonbalrog with the glaive.. Instant death.
Anybody else come across this?
The only damage upgrades I had was cursed bullets and snowballets. I had no synergies with the kruller either.