Vampire Survivors

Thx!

Do I have to do this every time I want to use the weapon, or would it be in a random upgrade after I unlock it for the first time?

@Biggquis78 Yeah this is seemingly only available if you upgrade the weapon yourself. It doesn't appear to be an option in the Super Candybox II Turbo drop which is quite rare anyway and needs you to have unlocked the Candybox and already had it drop for you on the run you're on before the better version is available.
They seem to update the game pretty often though so they could add other methods to get the weapon in the future.

good guide

The Clock Lancet is the starting 'weapon' (which just freezes enemies) of Iguana 'Gallo' Valletto - it kind of looks like a blue and white snail. However, you can't select Gallo to get this achi/Infinite Corridor because he's unlocked by getting it.
I'd do this on Inlaid Library (easiest map), going left for the Silver Ring first, then back to the right for the Gold Ring.
Picking 'Out of Bounds' or 'Blood Astronomia' Arcanas allows the Clock Lancet to deal damage.
I managed to get the Infinite Corridor and Crimson Shroud first go, on the same run of Inlaid Library, albeit with just 4 seconds left - that's a bit trickier because neither Clock Lancet or Laurel are real weapons, so you have to upgrade proper weapons at the same time, and Infinite Corridor and Crimson Shroud need many upgrades to get them. Remember to leave some V chests for when you're ready to get the evolved versions - when the component items are max level 8.