Out of depth
For the other OOD, see Orb of Destruction.
Crawl tends to create many out of depth (OOD) monsters, or 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.
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.
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 often aren't considered OOD).
- Monsters can spawn in pregenerated vaults. For instance, one Lair entrance vault contains death yaks. Death yaks don't naturally spawn in the Dungeon at all, but are very tough enemies for D:8.
There are some hardcoded assurances that certain, ridiculously difficult monsters can't spawn - water moccasins can never spawn on D:2, though they can spawn on D:3.
Out of depths are most noticeable in the Dungeon: it is the longest branch, ramps up in monster strength between floors, and is explored when you don't have as many options to escape. In other branches, out of depths can still be an issue, but less. For example, most characters will find D:5 killer bees deadlier than Depths:2 caustic shrikes. Later on, unique monsters fill the role of an "above-average monster".
When encountering an out-of-depth monster, check the monster's description, especially the speed and range, and determine if you can just walk away.
- An OOD ogre or hydra might have brutal melee attacks, but they are 100% speed melee enemies. If nothing's in the way, you can just walk away if you see them. You can then go up stairs, then enter the floor from a different set of stairs.
- An OOD orc priest can be extremely scary - it has 17 damage Smiting that can attack from anywhere in sight. But if the priest is at the edge of your line of sight, you can also walk away (since monsters cannot attack outside LOS, and orc priests aren't fast).
- An OOD centaur is faster than all players (except Spriggans) and have a ranged attack. There's no running away, at least without using an item.
Tips & Tricks
- Use your consumables! Especially if you can't escape by simply walking away.
- If all else fails, you can simply skip the floor and descend downwards. After all, D:11 and Lair:1 are, most likely, less dangerous than a D:10 with a wandering storm dragon. Even if the floor below would be dangerous, you can at least check out what's actually in store (and decide from there).
- 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.
- mon-pick-data.h:1 (0.30.1)