As Jason Chen at sister site Gizmodo aptly points out, those are not onions. He should know! Dude loves onions.
Spotted at a Japanese arcade, this very retro looking crane game is packed with boobs. These palm-sized tension-reliever novelty items that have been available in Japan (and elsewhere) for some time. They're quite squishy and hard to grasp with one's hand, let alone a metal crane.
This is the first time we've seen them as a crane game prize and are adding it to our list of suggestive items we've found in crane machines: glow in the dark undies, handcuffs, porno DVDs. The list, like life, goes on and on.
Japanese Boob Claw Machine [Gizmodo]