Soultorn

At 1 in 8,333,333, Soultorn is a Mythic you can plan around: about 8.3 million rolls at 1x luck and roughly 833,000 at 10x, with no biome in the way. The wiki says it came with Eon 1-23, lists it as obtainable and credits reeseyhi and TRMG_YT. There is no in-game description recorded for it.

The name is literal. When equipped, the player levitates while a shadowy figure above them, meant to be their soul, copies every animation they make. The eyes go dark, and six black and green spikes of different sizes surround the character, one of them carrying a lantern that casts green light. Now and then the word REC and a running timer flash briefly on screen before fading, as if the whole scene were being recorded. The cutscene is a half black, half dark green eight-pointed star that spins while it grows, until a lighter green and black background reveals the aura. It uses the Italianno font and has no active ability.