Pink Fairy

A fairy is a guide dog for loot. Once it is active it flies over to you, hangs at a short distance so you have something to follow, and when something valuable enters its search box it circles you, chimes, and sets off toward the target. Arrive with it and it spins once and pops in a shower of light that briefly lights the room. It moves through blocks, takes no damage and cannot be caught while it is working. It also expires: a few minutes after it appeared it leaves, whether or not it was halfway through leading you somewhere.

Underground fairies exist only because logs do. They spawn in the lower half of the Underground and through the Cavern layer, but the game first checks that at least one fallen log is still standing on the surface. Clear cut every log in your world and underground fairies stop appearing permanently, which is an easy mistake to make while gathering wood. Their rate also drops once the world goes into Hardmode.

The fairies that appear at fallen logs after dark, or fall out of a shaken pearlwood tree, are a different animal. They lead nowhere, they flee from you like a bird, and a Bug Net works on them. Release a netted one anywhere and it switches into treasure hunting mode, which is the only way to run a fairy on the surface or in a spot you chose. The other option is crafting it into a fairy jar, and that is one way: the jar only gives the fairy back through Shimmer.

The night spawn is narrow. It happens in a window in the small hours, once per log per night, with better odds on new and full moons. Rain blocks it, so does the Moon Lord arriving and most invasions and moon events, and a log that is on someone's screen will not produce one. Remix worlds open the window to the whole night. Journey Mode time controls scale the rate directly, so speeding time up is the fastest way to gather a stock of them and freezing time stops them completely.

Fairies sweep a wide rectangle around themselves looking for chests, life and mana crystals, life fruit, strange plants and the valuable ores from gold and platinum up through chlorophyte. Ore has to be a real deposit rather than a stray block or two. When several things qualify it picks the same winner the Metal Detector would, which is why wearing one is worth it: you learn what you are being walked toward before you get there.

The awkward part is that a chest you already emptied still counts, and so does anything you placed yourself. If you use fairies seriously, break chests after looting them or you will spend a lot of time being escorted to your own furniture. Watch for dead man's chests as well, since a fairy leads you to one as happily as to a real prize, and it can point at treasure sitting outside the world border where nobody can follow.

A fairy near you suppresses enemy spawns for as long as it lasts, using the same effect a sunflower provides, and the two stack. It also registers on the Lifeform Analyzer, which is the easiest way to know one has appeared before you catch the light out of the corner of your eye. The three colors behave identically, so pink is purely cosmetic, though a Celebration Mk 10 world makes almost every fairy pink and raises the cavern spawn rate on top of it.