Menace

Back Tap Banshee

Set the phone down hard and it shrieks.

Build it by hand ↓⏱ 30s setup

What happens

Double-tapping the back of the phone plays a banshee shriek. Setting it down may accidentally trigger Back Tap, but that is not a reliable trigger.

Setup

Save a short scream sound in Files. No shortcut download is supplied for this manual build.
Open Shortcuts → +, name it Utility, add File, select the scream, then add Play Sound using the File action’s output.
Run it while unlocked, allow file access, and check media volume and audio output.
Settings → Accessibility → Touch → Back Tap → Double Tap, scroll to Shortcuts, and choose Utility. Double-tap the back to test it.

Undo

Settings → Accessibility → Touch → Back Tap → Double Tap → None, then delete the shortcut.