What is the deepest and scariest planet you've found?

Now that we have truly deep ocean planets, I'm curious as to what the deepest ones you've found are? And what's the scariest creature you've found in one?

For me personally, I found a planet that I've started a base on, it's a bit over 1400u below the surface. So I'm unsure how deep it goes, but needless to say my game says it's the deepest I've found so far. It also has giant squid, probably 6 to 8 nautilus's in length, they aren't aggressive but because the water is so murky they pop out and scare you half to death.