Wither Rose farms are something I always wanted to build but am too intimidated by.
Wither Roses are useful for mob farms since they can kill mobs with the Wither effect, and is one of the two farmable sources of black dye, the other being ink sacs. However, Wither Rose farms require having a Wither, and they are not the most cooperative mob out there.
The most reliable Wither Rose farm design I’ve found so far is by Rays Works, and is almost foolproof. However, it needs to be built in The End. And honestly, I do not want to travel all the way to The End for a single farmable resource that isn’t even vital for survival. Thus, I tried to design one that works in the Overworld.
It all started when I had a sudden brainwave one day: are waterlogged slabs blast-proof?
With a waterlogged slab setup like this, I can have an air chamber below to house my Wither. That way, I can dump mobs into the chamber for the Wither to kill. A Wither can’t drown, but if I have a water-fill chamber the mob might either die from drowning first or float to the top. If the mob floats to the top, the Wither will start shooting towards the roof, so I need to blast-proof my roof either way.
After placing around 50 TNT Minecarts right below the waterlogged slab roof, I flipped the switch.
And the test is really encouraging! The roof survived intact while all the sandstone within the blast radius were obliterated. Thus, I begin to build my first prototype of a wither containment chamber.
I have a wall of water shielding the wall of my containment chamber. My assumption is that since explosions underwater can’t destroy blocks, I should be able to keep the wither contained. And with the gap there, I can maybe drop mobs through it for the wither to kill. To test this, I spawned a wither inside.
Yeah, it didn’t go well.
The Wither managed to blast through the water curtain and obliterate the red sandstone wall. It then slipped out and left my test world looking like the Moon.
At this point, I assumed that the only reason the waterlogged slab roof survived is because it is a waterlogged block. So I built another version with waterlogged fence walls.
Unfortunately, the first version, with a one-block gab between the fence and the roof/floor, is a failure, since it just turns the whole chamber into water source blocks.
I rebuilt it with a two-block gap between the fence and the slabs so that I can still have an air chamber. Since all the blocks are waterlogged this should work right?
Nope. The Wither does not care.
And after another test, I realized the only reason the waterlogged slab roof survived is because the Wither didn’t shoot up. It can destroy waterlogged slabs just fine.
According to the wiki, the more destructive blue Wither skulls simply treat all blocks as having a blast resistance of 0.8, which means that it is guaranteed to destroy it. Water normally “shields” other blocks with their 100 blast resistance, but the blue wither skulls simply ignore it.
I went to check the wiki to see what else are immune to Withers. According to the wiki, moving piston blocks are immune. It’s pretty easy to rig up a Redstone clock to keep a bunch of pistons moving. And after making a moving piston floor, I stopped. I had just realized what I was making.
I’d just built a lag machine.
After all these attempts, I give up. I’ll stick to squid farms for my black dye next time.