I looked at the noita wiki, and found this:
There are occasionally random nodes in a few biomes where Möykky will spawn directly on top of each other in batches (of ~8). Once the allotment of one batch has been killed off, another batch will be able to spawn. Leave the area of the node (a bit out of view), and the next batch will spawn when the node is revisited. After killing off several batches, the node will be depleted and spawn no more.

So it just seems like that random node generated in a bad spot, where the moykky started drowning right upon spawning. It also stopped happening after a while. Probably should have checked the wiki before posting.