When:
Anytime from the start of the game, after reaching LEVEL 4 in a run.
Method:
Destroying light sources has a small chance to spawn a temporary power-up instead of the usual coin / chicken.
One of these power-ups is the Orologion, an item which freezes enemies for 10 seconds. Collect this! The first time you do you'll unlock the CLOCK LANCET for use in future runs.