surprisebutton
nounUK /səˈpraɪz ˈbʌtən/
US /sərˈpraɪz ˈbʌtən/
A button you press to make something fun and unexpected happen.
She pressed the surprise button and a toy popped out of the box.
OTHER MEANINGS
2. A hidden control that reveals a secret message or prize.
The website had a surprise button that showed a funny cartoon.
3. A game button that gives a random reward.
Tap the surprise button to win a sticker.
4. A party gadget that makes a sudden pop or sound.
The birthday cake had a surprise button that played music.