Invoke

Transmutation Cantrip (Bard, Sorcerer, Warlock, Wizard)

Casting Time: 1 action
Range: 20 ft.
Components: S
Duration: Instantaneous

You weave harmless magic that's your choice of visible, audible, or tangible (without being able to create a specific shape, sound, or feeling) that is very apparent to all creatures within range. Creatures trained in arcane magic will always know which cantrip you casted, specifically that it isn't harmful to them.

Magical objects or effects within range will react to it in trivial ways (for example, a magic light might flicker, the glow of a magic weapon could alter its hue or intensity, or an invisible magical aura might become visible as dust motes).

Nonmagical objects are not affected in any way by this spell.