Lyric discussion by Ktgkyle 

Cover art for Kalopsia lyrics by Queens of the Stone Age

I think this song is about taking off your mask and embracing who you are. Being as the character in this video is a ugly monster. He takes off his mask and sees happiness then is killed by a man who does not accept him.

My Interpretation

especially consider that the word Kalopsia literally means "The delusion of things being more beautiful than they are"