Just discovered this RNG-based strategy. I can get it in about 1 out of 10 attempts.

This is the fastest Level 1 Boss known, killing it in 1 cycle. Saves 2.5 seconds in time compared to the World Record Speedrun (which is a 2-cycle)

1. Let the boss kill you
2. Stand at THE EXACT position you see in the video, else it won't work (one pixel to the left and it will still work but he will do another jump and THEN die, which is still faster and I'd call that a 1.5-cycle)
3. Hope for good ceiling RNG (if one of those things spawn on your position it usually won't work / you'll exit the boss with not enough HP to finish the rest of the lvel fast)
4. Aim at the boss once you are stuck at the ceiling. Strat is also viable in speedrunning because you usually exit the boss fight with almost full HP.