WHAT!? WHAT IS THIS WALL!?

OKAY! I am upset. I was doodling Yin and Yang doing something all light hearted and happy (it was supposed to be them building stuff out of clouds) but noooooooooo...

This black wall came down out of nowhere and separated the two. I can't erase it! I didn't draw that. I don't even think it's sharpie ink! Too hyper-realistic.

Needless to say, they don't like being separated like this. Glancing back at the whiteboard as I post this, Yin is now singing to try and calm Yang, who is in a fetal position crying.

How do I get rid of this wall?!