Cobweb

Placed webs catch you mid fall and wipe the damage you were about to take, which makes them the low tech floor at the bottom of a shaft. They also come apart while you are stuck in them, one tile at a time and quickly, so a thin layer is a single save and a deep plug survives several. That is the whole design decision: how many falls do you want this pit to absorb before you refill it.

Two things they do not do. Enemies, town NPCs and critters walk straight through untouched, so a web wall is not a barrier and never will be. And a minecart shreds them on contact instead of being slowed, which matters if you run track through a natural cave and expect the webbing to act as a brake.

The strands hanging along walls and ceilings in ordinary caves always drop when broken, and they come out fastest to a swung weapon or tool rather than a pickaxe, which is worth remembering when you are clearing a room in a hurry. They cluster, so finding one usually means finding a handful. Dangersense outlines webbing on screen the same way it outlines traps, and that is by far the quickest way to spot a pocket you would otherwise walk past.

A nest is wall to wall webbing, and most of what you break in there gives you nothing at all. The trade is that the walls regrow it. A nest you have already stripped refills on its own, which makes it the only renewable source and the right place to go when a project needs hundreds rather than dozens. Clear it, leave, come back to a fresh sheet.

Almost everything downstream routes through Silk first, so treat raw web as a currency you convert rather than a material you use. Rope is the clearest case: going the long way through silk to make Silk Rope stretches a given pile much further than making Web Rope directly does, and gives you more rope at the end. The web itself is worthless to a vendor, so if you are selling rather than building, convert before you walk into the shop.

The rest of what it feeds is scattered across the game instead of concentrated in one tier: an early yoyo, the potion that reveals traps, a hardmode whip, and a set of spider themed building blocks. None of it is urgent, which is why most players end up with a pile they never touch and then a sudden shortage.

In expert remix worlds the web spit from a Black Recluse or a Jungle Creeper does more than slow you down. Where the projectile ends, it plants fresh webbing across a wide square. That cuts both ways: the fight leaves you standing in a harvestable pile, and it also leaves you standing in something you have to chew through while the spider is still on you.