Fire-Breathing Statue

Magic trap with a mechanical trigger
A Fire-Breathing Statue unleashes a magical gout of flame when an intruder steps on a hidden pressure plate. The statue might depict a dragon, a wizard casting a spell, or any other figure suited to its surroundings.
Detecting the Trap. A character who succeeds on a DC 15 Wisdom (Perception) check notices the pressure plate and faint scorch marks on the surrounding floor and walls.
A spell or other effect that senses magic, such as Detect Magic, reveals an aura of evocation magic around the statue.
Trigger. The trap activates when more than 20 pounds of weight is placed on the pressure plate.
Effect. The statue releases fire in a 30-foot cone. Each creature in that area must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much damage on a successful one.
Disabling the Trap. Wedging an iron spike or another suitable object beneath the pressure plate prevents the trap from activating.
Casting Dispel Magic on the statue and succeeding on a DC 13 spellcasting ability check permanently destroys the trap’s magic.