The trap is calibrated to activate when the player’s XP level ends in 69 or 420. Using a comparator and an XP storage system (decorated with amethyst and copper), the trap reads your level.

The phrase "lovely craft piston trap funny number best" refers to a specific subgenre of viral content and internet memes, primarily centered around the indie game Lovely Craft

Recent versions of the game (such as v.0.2.999) have significantly expanded the roster and features: New Characters

Built a beautiful little piston trap in Minecraft today – looked cute, worked smooth, and then... BAM.

This is the most important part. A deadly trap looks scary; a trap looks inviting.