Pen tool left mark on artboards, when making new artwork it still appears

[Sarah33759750hgdu]

I used the pencil tool to make a random shape, but now I can not remove it, and its there on new artboards or old files I open?

I deleted the actual shape it made (or thought I did) and now i've just left with the outline 

You can see below I've opened an A4 new tab and its still there, and A3 landscape tab and its still there.

I have shut illustrator down and reopened and its not dissapearing 

Any help would be appreciated!

Thank you!

[Monika Gause]

Is it still there in the Layers panel?

[Sarah33759750hgdu]

No, as I'm opening fresh artboards up and it's still there 

[Monika Gause]

Can you please show a screenshot of the Layers panel?

What do you mean with opening fresh artboard?

Are you creating new files? Or just new artboards?