The Rime of the Frostmaiden adventure book has this:

https://5etools-mirror-2.github.io/adventure.html#idrotf,12,b4.%20main%20room

A character killed by the Summer Star becomes an ethereal spirit bound to the Black Cabin

It's a DC 17 CON saving throw for 10d10+35, save halfs. This is at around character level 5-6. Rogues searching for shines are gonna have to shut the fuck up for the rest of the session. Unless you roll like garbage and they roll like gods, in which case... Idk man, they've earned it, let them enjoy it.