Ghost

From LSWiki

This is what you become after you die. Most people revive quickly, but there are some benefits to staying as a ghost for some time.

Ghosts are intangible and have wingless flight. They also are ametabolic, have breathing of None, and are undead.

They also seem to have +1 night vision, or otherwise paravision, such that they can see in many places.

They are not bothered at all by autonomoi (NPCs).

However, they can't undertake countless typical actions, such as speaking, or emotes. They also don't have inventories (except for extraordinary cases like teleporting from Lakan via the silvery rod, which places the Talisman of Kalkin into your ghostly form, dropping it after you disincarnate).

Being a ghost is excellent for exploring.

Reapers can turn and return from being ghosts whenever they wish thanks to the Ectoform power.

Some Riddlemasters spells seem able to turn you into a ghost (needs more confirmation).

Ghosts cannot gain any experience beyond their maximum limit before advancing. For example, if you are level 35, you would need some XP before advancing, and be able to gain up to 80,000 beyond this. As a ghost, you will gain XP until this limit: you may notice it by explore XP messages ceasing. To successfully advance, you will need to revive: if you were truly at the limit, you need to kill a NPC to get the advance mechanism working again.

All the XP you would have gained otherwise is lost.