Digtoise

Nothing crafts it and nothing drops it. In the Underground Desert a Sleeping Digtoise occasionally generates in place of a cluster of Antlion Eggs, rare enough that you will pass a lot of eggs first. A Metal Detector picks it out and the Spelunker glow highlights it, but a Lifeform Analyzer and the Hunter buff both ignore it entirely. There is no boss gate, so an early find changes how the whole world gets dug. Remix worlds confine it to a band in the upper part of the map instead of scattering it at normal desert depth.

Using the item drops the turtle on the first solid block under your cursor, ignoring platforms and sloped blocks, so aim at real ground. With the item held, clicking sends it rolling toward the pointer. It bites in when it meets a wall and keeps chewing a three tile wide tunnel in that direction with no further input from you. Clicking open on any empty part of the screen stops it. Clicking on the turtle itself pets it, which is worth knowing before you try to stop it and give it a scratch instead.

Set it digging and go do something else. A hellevator is the obvious job and it will cut straight through liquids on the way down. Multiple players can each run their own without interference, which turns a group into a fast excavation crew with no explosives involved at all.

• Its mining power is weaker than any actual pickaxe, so hardmode ore or a Dungeon wall ends the run on the spot.
• Digging sideways it needs floor beneath it. It rolls over a single missing tile and stops at anything wider.
• Shimmer does not stop it, so sending one down near the Aether can punch through the pool and drain it.
• Check on it. A tunnel that stalled ten minutes ago is time you do not get back.

The Digging Molecart is faster for horizontal tunnels and lays its own track as it goes, so it never runs out of floor, but it is considerably harder to obtain. The Digtoise has one trick the cart does not: it sets off contact traps like a Rolling Cactus while you watch from a safe distance. Once you are done with it, Rubblemaker (Medium) can put it back down in its sleeping form as decoration.