Disc of storms

Version 0.13: This article may not be up to date for the latest stable release of Crawl.

Type	Miscellaneous item
Name	Disc of storms
Icon

This extremely powerful item can unleash a destructive storm of electricity. Its effectiveness greatly improves in the hands of one skilled in using magical devices.

A disc of storms is a powerful evocable item which releases uncontrollable (and dangerous) electrical bolts when evoked. Unlike other evocable items, it does not become inert after use, and has no hunger or MP cost; the only thing preventing a player from spamming it endlessly is the fact that the storm it releases can punish you as much as it punishes your enemies. Its success rate rises with Evocations.

Evocations	Success Rate
0	34%
5	42%
10	51%
15	61%
20	73%
27	91%

When the disc is activated, 2d(1 + Evocations/7) bolts are zapped at random tiles up to 6 tiles from you (including your tile). These bolts may be bolts of lightning, bolts of electricity, or orbs of electricity (equal odds for each).

Using this item has an Evocations-based chance of creating rain clouds in the area surrounding the caster. This can turn regular tiles into shallow water and shallow water into deep water. It is therefore not recommended for use in the vicinity of your stash, nor to use while in shallow water unless drowning isn't a risk for you.

Nothing happens. (Evocations failure)
The disc glows for a moment, then fades. (Evocations failure)
Little bolts of electricity crackle over the disc. (Evocations failure)
The disc erupts in an explosion of electricity! (Success)

Strategy

One should not use this item without understanding that you are going to take damage in the process. With electricity resistance, you can still find yourself taking up to 30 damage per use; without it, much, much more. Characters with small HP pools and who lack electricity resistance should probably set this item aside entirely. Those who do have significant amounts of life and rElec, however, can get immense amounts of damage output in a very short amount of time when surrounded by enemies; you are effectively casting up to 2d8 powerful spells for free in a single action.

Used in a wide open area, the majority of your bolts will fire wildly, hitting nothing, while your orbs of electricity will detonate, devastating everything nearby. Used in a narrow hallway, the bolts will reflect off the walls, likely multizapping everything nearby (including you). At the end of a dead-end hallway, you'll wind up multizapping yourself repeatedly while hitting almost none of your enemies; avoid using the disc when it's this blatantly suicidal.

Because using it has no cost aside from the turn spent evoking it, a character at full health, suddenly surrounded by opponents, can spam it to good effect. Just make sure you know what you're getting into before attempting this though. Try using it in a safe location at full health, just to get an idea of how much you'll be brutalizing yourself with each use.

Calculations

The probability for successful evoking it is: (0.7 + Evocations/100)³

History

Prior to 0.12, the disc was unusable if you had electricity resistance.

Prior to 0.9, it appeared unidentified, as a grey disc.