This video is called Comma (Polygonia c-album) butterfly.
Translated from the Dutch Vlinderstichting entomologists:
Jan 19, 2016 – There are four butterfly species that traditionally spend the winter in the Netherlands as butterflies. They curl up in sheltered spots and wait for the first spring days to become active and to reproduce. Peacock and small tortoiseshell often go to sheds, attics and old military bunkers for this. Comma butterfly and brimstone winter in bushes and fagots.
But while checking bunkers on the presence of hibernating bats Kees Mostert found on the border of Germany and Poland a comma entirely at rest. This is very unusual, and as far as known, this has not been seen before in the Netherlands. For many years, the bat counters also have been looking out for other animals they encounter in the bunkers. They often see peacock and small tortoiseshell butterflies and also moths like the herald moth and buttoned snout are regularly reported, but so far no comma.