Silly

First launch: macOS will say the app is from an unidentified developer (it’s an early build, not yet notarized). Right-click Silly.app → Open → Open. If it still won’t open, run in Terminal:

xattr -dr com.apple.quarantine /Applications/Silly.app

Silly lives in your menu bar (the 🎉 icon). Click it, then the ✨ button to preview the animations.