Gacha-Gacha in Haneda airport too! Did you try it already?
Gacha-Gacha is a capsule toy dispenser. Throw coin(s) into the machine and turn the lever, then a toy in a capsule comes out.
Quite familiar toy machine in Japan for long time though, recently a toy maker placed the machines in Narita airport then it became super popular among foreign tourists.
You can use leftover coins and get interesting souvenirs just before leaving Japan
Here is gacha-gacha video