Out of depth

Version 0.28: This article may not be up to date for the latest stable release of Crawl.

Crawl tends to create many Out of Depth (OOD) monsters, who have spawned on a higher floor then where they are "usually" spawned. The source file mon-pick-data.h defines where is a monster's base floor is, so anything above that is technically OOD. The term typically refers to non-unique monsters which are much more difficult relative to where you are in the game, such as a sky beast on D:2.

Creation

Like all monsters, out of depth monsters are spawned when the floor is generated. Their 'base floor' is fuzzed, favoring the actual number, but often either up or down. However, there are also a few special cases with monster spawns, which can break the "normal" rules of generation.

• Monsters can often spawn in "bands", which have their own depth. Despite orc priests naturally spawning on D:4, they can spawn on D:3 or even D:2 as a part of an orc band. (Because this is common enough, D:3 Priests aren't often considered OOD).
• Monsters can spawn in manmade vaults. For instance, one Lair entrance vault contains death yaks. They don't naturally spawn in the Dungeon proper at all, but are very tough enemies for D:8.

There are some hardcoded assurances that certain, ridiculously difficult monsters can't spawn, such as a D:2 water moccasin.

OODs are most noticeable in the Dungeon, which has the most monster variety, and when the player doesn't have many options to deal with them. Many later branches don't have many floors, don't get much harder between floors, and many don't gate monsters by floor to begin with (harder monsters just spawn more rarely). Unique monsters tend to remain challenging later on.

Strategy

• Check the monsters speed and range, and determine if you can just walk away. An OOD orc priest is extremely scary, with its 17 damage Smiting that reaches the entire screen. An ogre or hydra are 10 speed melee enemies, meaning you can just run away if you see them. The same applies to the 10 speed orc priest, but only if you can keep it out of sight (where monsters can't attack).
• Use your consumables! Especially if you can't escape.
• If all else fails, you can simply skip the floor and descend downwards. After all, D:10 most likely won't be as dangerous as a wandering D:9 fire dragon guarding the Lair. Even if it'd be dangerous, not only is it safer than near-certain death, but you can at least check out what's actually in store (and decide from there).

History

• Prior to 0.21, monster spawning was used as a means to create out of depth monsters. If the out-of-depth timer went on too long, then it became more and more likely for these difficult monsters to spawn.