LF

Looking for this manga that I thought was pretty cool but I forgot the title.

Basically it was about this entity that landed on Earth which could take the form of anything on Earth. If I recall correctly it took the form of a rock at first, then a dead wolf in the snow. He went to the wolf's owner's (a boy) igloo and met his family who were moving. After that he was alone with the boy who eventually died while trying to find his family. This entity that took the form of the boy.

If I'm not wrong, its' whole purpose is to take the form of a stronger being each time.

Well if you know do help, thanks!