We have a 4yr old spayed, indoor cat who goes out of her way to find plastic and eat it!
She has always been this way - we got her at 4 mos. old. Her favorite is the plastic from grocery shopping bags: she hears us crinkle them to put them away and she comes running!
Yes - we know it's not healthy for her! We hide all plastic from her reach! We can't even have the bags hanging from waste baskets!
Does anyone have a clue as to why she's got this weird behavior?

The vet can't figure it out, since she's healthy.