Alien- no.

This is a cicada emerging from its shell. The life cycle can last for 17 years! This is the stage where a nymph which has been living underground emerges and crawls up a tree or wall and the skin splits on the back of the neck. The adult stage emerges from this split. The structures sticking out at the side, eventually after about an hour, became the wings. Cicadas are grasshopper type insects but they can fly. The adult is about the size of a large thumb and they are very noisy, making a chattering or rattling sound. It was fascinating to watch.