Cloud forms on my starter

Okay, so I'm fairly new to sourdough starters. My first batch of starter went great (not as sour as I'd like, but yielded a perfect bread) I then, being so new at it, forgot to feed her for a few days and she died. I discarded and started over. Now, after one to two days of starting the new starter I get a cloud-like formation over top of my starter EVERYTIME. I wasn't sure what it was as it wasn't discolored so I mixed it in and fed her again. Two days of this, and there is now mould on the side of the jar. I panicked and discarded the entire thing again. I need advice on what I'm doing wrong here?! Why is it molding and what is the cloud? I'm getting a little shy away from sourdough bread, which would be a shame as it is my absolute favorite.

Please help.