Alarm trap
While this trap does no damage by itself, its loud sound may bring someone to do damage to you. Of course, you have the option to do damage to those someones yourself. |
An alarm trap is a trap which produces a loud noise (intensity 12, the same as a shout) when stepped on by either you or a monster, alerting anything nearby. If you step on one, it also afflicts you with the Sentinel's Mark status effect (ignores magic resistance). Alarm traps are magical traps, and can thus be set off even by levitating beings. After triggering once, they disappear.
Alarm traps cannot be disarmed, but can be silenced.
Strategy
If you're travelling through an early floor you've already cleared, find an alarm trap, and need a quick bite, stepping on it is not a bad way to summon any potentially edible opponents to you.
History
Prior to 0.12, alarm traps could activate multiple times before breaking, but they did not afflict you with the Sentinel's Mark.