Ghost (HD)

The Ghost is the ultimate danger in Spelunky. It is near-unkillable, it can not be deterred, and one touch is guaranteed death.

Fortunately, it is possible to make it through the entire game without ever seeing it.

Unlike many enemies in the game, the Ghost is more of an incentive than an obstacle. It exists to prevent loitering by greedy treasure hunters, and 'turtling' by the more pusillanimous of defilers.

Instead of allowing the player all the time they need to meticulously sweep every level of treasure and to take as long as they like to creep around difficult traps and enemies, the Ghost introduces a dynamic of play where risks must be taken and good judgements must be made quickly.

By putting pressure on players to improve, the Ghost ensures that the only way to be successful is to hone your skills and play well.

Strategy

The Ghost is (almost) unkillable, and will pursue the Spelunker relentlessly. The only real 'strategy' available is to simply run away to the safety of the level exit.

It is possible to temporarily stun the Ghost by taking a picture of it with the Camera, which causes it to pose humorously. This does little more than delay its pursuit, but the brief second it spends distracted might just be all the time you need to slip past it and get out of an otherwise hopeless predicament.

It is possible, albeit extremely difficult, to kill the ghost. The ghost has 9999 hit points, and only takes damage on entering lava (99 damage) or by a UFO shot passing through her (1 damage). There is no death animation when her health reaches zero - the ghost simply disappears.

This feat was performed on 11/28/2013 by Bananasaurus Rex. Here is a video of this feat happening [TO BE UPDATED]

There are three circumstances where the Ghost is summoned:

Time Limit

After 2 minutes and 30 seconds spent on a level, you're given a warning: "A terrible chill runs up your spine!".

This signifies the arrival of the Ghost, who appears from beyond the edge of the level closest to the Spelunker.

Its ominous appearance causes the atmosphere of the level to change as a spectral fog sets in and the background music becomes distorted.

At this point you should prepare to leave the level as soon as possible, but this deadline is negotiable if you are able to evade the ghost and avoid being cornered.

The Ghost does not spawn in this manner on levels 4-4 or 5-4, as these are special 'boss levels' that are expected to take a long time.

Disturbing the Crystal Skull

The second instance in which the Ghost can spawn is on a Restless Dead level. If a Crystal Skull appears on that level, picking it up will immediately cause the Ghost to spawn.

If the Ghost has already arrived on the level, picking up the Crystal Skull will actually cause a second Ghost to appear from a side of the level.

Kali's Anger

Finally, destroying three or more of Kali's altars in a single game will enrage the vengeful goddess to the point of immediately spawning the Ghost. You will have to deal with the Ghost in addition to being shackled with the Ball and Chain. Though this won't affect the invisible level timer, no further ghosts will spawn if it hits 2 minutes and 30 seconds.

The Ghost will then spawn in every subsequent level immediately after entering, even on 4-4. This will make it impossible to beat Olmec, as the Ghost kills the Spelunker during the opening cutscene. It is unknown if this is intended behaviour or a bug.

Ghostrunning

Risk vs. Reward

For the daring and agile, the Ghost can be used to generate extremely valuable diamonds.

When the Ghost passes over large rubies, sapphires or emeralds lying on the ground, they will be transmuted into diamonds worth several times the value of the ordinary jewels. Gems still embedded in rock will not be affected.

Unearthing jewels and leading the Ghost over them deliberately is known as Ghostrunning, and can result in astronomically high scores if done well.

Trivia

The Ghost may be a reference to the ghost from Spelunker, but it functions more like Baron von Blubba of the Bubble Bobble series, who operates as an invincible (but avoidable) enforcer of the stage time limit. Baron von Blubba is accompanied by an ominous theme tune, much as the Ghost in Spelunky warps the background music when it appears.