Biodegradble bags are biodegradable

I've just found out that biodegradble bags are biodegradable - the hard way. When I went to check whether I've bought a manga twice, I found that some of the plastic bags I used to store my manga and my Snape costume by the window had disintegrated. Flakes of plastic fell down to my bed when I tried to clean up the mess. I guess this just isn't my day, but at least now I've seen firsthand what a bag in the process of degradation looks llike.