When Teardown was still in development, developer Dennis Gustafsson would occasionally post screens or videos of the work-in-progress. At one point, there were spiders, but then they vanished. Where did all the spiders go? At the time Gustafsson explained that they were for a prototype.
"I'm glad you liked the spiders. I did too," he said on Twitter. "They were for another prototype I worked on and I'm not sure they fit it into this concept, but who said you cannot steal things from an underground lab filled with monster spiders?"
Teardown did not, in fact, launch with spiders. But they were still in there! Over the game's first few days the community worked out how to add spiders back in via a simple script and, even better, you could spam it to add loads. Fill your boots with spiders!
If you want to see them in action you can watch the first half of this video. The spiders seek out and can damage/kill the player, and you can spawn in as many as your poor PC can handle. Unfortunately, trying this yourself will only end in failure.
Why does the trick no longer work? Because nothing is forever, chum. Yesterday an update removed the spiders, and Gustafsson explained why on the game's Discord: "Spiders removed. They were included by accident. Since they neither look or act as we intend them to, we remove them as not to spoil their comeback in the game."
Wait, comeback?!? Spiders confirmed!