The Cloud Seeder is a new structure crafted from Shroom Skin and a Fleshy Bulb. It looks like a big puffball mushroom, with a small opening at the top. The blueprint for it is obtained from killing Toadstool.
This structure has 2x2 inventory slots, but only Spores can be put inside. The Cloud Seeder can be hit by players as if it was a mob, but it can never be killed. Instead, the point of hitting it is that every hit will shoot a Spore from its opening into the sky, consuming the spore. Each Spore released this way will make the next rain happen a little bit sooner, similar to using the Telelocator Staff.
The idea for this item is that it would give players another reason to kill Toadstool, a boss that a lot of people find the drops to be underwhelming, give Spores more uses (which tie in with Funcaps, dropped by the same boss) and let players have some control over the weather. Rain is very useful when it comes to using electric damage which DST seems to have a bigger focus on (with Electric Darts and Volt Goat Chaud-Froid) but it's also a global way to prevent wildfires from happening, rather than limited ways like an Ice Flingomatic or the sandstorm.
Speaking of wildfires, I mentioned the Telelocator Staff has a similar function of making the next rain happen sooner, but during Summer this means about ~20 uses of it for a single rain, which is incredibly expensive, especially considering rain doesn't last very long in summer sometimes. Spores would be a more reasonable but also more interesting cost.
The idea behind the name is that it's something that literally does "cloud seeding", which means releasing chemicals in the clouds to cause rain. In this case it's even more literal than that, releasing actual "seeds" (spores) into the clouds.
I've had this idea floating around my head for a long time, even if it doesn't make it into the game I hope you found it interesting~ Thank you for reading 