Entomology (Study of Bugs)/hanging insect cocoon?
I live in Mumbai and have found these hanging in the bathroom. Yesterday while cleaning under an old wooden bed I found maybe 50 hanging. Horrible sight. The are usually dangling from ceilings but I have seen them stuck to the wall. They do not seem to move and seem like the shell of something.
You are absolutely correct - it is indeed a cocoon. The caterpillar of a small moth barely measuring 1 cm in length, brownish in colour, builds this protective cover around it self and drags itself around it much like a snail. Several moths exhibit this behaviour. The most common family is Tineidae. They are commonly found in homes, especially because of bird nests around.
They are completely harmless creatures. Once they are ready to form a pupa, they select dark places such as the wooden bed as you mentioned. The outer case seen in your photograph is actually made up of tiny dust and fibres found in our homes.
I hope this helps.