Ankhalade's Alarming Illusion

You create an illusion of an object or area within range that lasts indefinitely until it is discovered, dispelled, or triggered. The illusion can be a sound, an image, or both. The illusion can end if you dismiss it as an action.

The sound of the illusion can range from a whisper to a scream. It can be your voice, someone else's voice, a lion's roar, a beating of drums, or any other sound you choose. The sound can continue unabated throughout the duration, at specific time intervals, or when a specific event occurs.

The image of the illusion--such as a door, muddy footprints, or a chest--must be no larger than a 10-foot cube. The image may be accompanied by acute sensory effects and small movements that add to the realism of the illusion but may not produce damaging effects or move outside of the designated area. Physical interaction with the image reveals it to be an illusion, because things can pass through it.

If a creature uses its action to examine the sound or image, the creature can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the illusion for what it is, the illusion becomes faint to the creature.

Additionally, you may choose an alarm to alert you if the illusion is discovered or dispelled. When you cast the spell, you can designate creatures that won't set off the alarm. You also choose whether the alarm is mental, audible, or both.

A mental alarm alerts you with a ping in your mind. This ping awakens you if you are sleeping.

An audible alarm may produce a loud bell or a spoken sentence in a voice of your choosing. The sound is repeated for up to 1 minute and can be heard from up to 60 feet away.

Upon activation of the alarm, those not exempt from the illusion and within the 10-foot cube, roll an Intelligence saving throw. On a failed save, they become Frightened for 1 minute. On a successful save, the audible alarm is disarmed.

The caster may only have a number of unique illusions active equal to his spellcasting level.