I'm updating these from oldest to newest, please bear with me.
This was a Christmas gift for my best friend, who loves Sans and Braixen.
And yes, a Marowak skull is the Gaster Blaster. Also fitting because Marowak is my favorite Pokemon.
This was made to be a 1920x1080 wallpaper, but it got shrunk down when I posted it to Tumblr. I'll fix the file size if I remember.