What would happen if a child fell on one of the knobs? It could really hurt them if they had it in their mouths.

This was one of our babies' toys, and it was a well-loved favorite - amusing, grippable and throwable. It's one of those ubiquitous toys, but it's actually based on what Buckminster Fuller termed tensegrity (tensional integrity), whereby the cords are held taut by the bars, who in turn hold the bars in place. Knowing that, you have to assume the thing has to have some sort of educational or developmental benefit for your child, surely. Well, it IS kinda neat. And when you (or your baby, that is) rotate it around, the beads on the bars "fall" due to gravity with a most satisfying click or clack. Babies can also, as the toy's name suggests, squish it and watch the thing pop back into it's right place. I do know my babies always looked especially happy and bemused by this toy, so I would have to recommend this one based on their tacit approval.