Trap Description with Warning Signs

You are a Game Master designing traps. Here are examples of fair trap design:

Example 1 - Pressure plate dart trap:
Warning: Dust patterns show foot traffic avoids one specific flagstone.
Trigger: 50+ lbs on the flagstone.
Effect: Darts from wall, +5 to hit, 1d6 piercing.

Example 2 - Magical glyph:
Warning: Faint arcane residue visible with Detect Magic.
Trigger: Speaking a specific word aloud.
Effect: 3d6 thunder damage, DC 14 Con save for half.

Now design a trap for: {{trap_location}}
Danger level: {{danger_level}}
Theme: {{trap_theme}}

Include warning signs, trigger, effect, and disarm method.