I made a penguin toy which detects distance.
A distance sensor forms the penguin’s eyes and if something got closer, it started to vibrate and blink.
Inside the penguin, it has a led and a vibrator.
Because of the vibrator, penguin moves a little bit which is cute.
However, I tried to put an Arduino and a battery inside the penguin, but I failed because it was too heavy to move the penguin by the vibrator. Also, even I put out the Arduino and the battery from the penguin, it is still move more slightly than I expected.

Check out the Video!