Ingrid chews those flimsy plastic grocery bags--also the cellophane from a CD wrapper. But she mostly does the former to get my attention, because she knows that it annoys/concerns me. I know she likes the noise.

As for the cellophane--I can't tell what the attraction is. Maybe it tastes a little salty? I'm mostly afraid that if she tries to swallow it, it might choke her or mess up her tummy.