Splotch

I think it's the white remnant of a dead frog (can't you see the legs to the right??)

BTW brilliant idea for a gallery!!

Or one of those Paleolithic cave paintings

I think it looks like a white human figure grasping a white object (i just woke up so don't ask me to be articulate!)

Actually, dead frog was my first guess...then, maybe some twisted parody of Michelangelo's Creation of Adam! (Where dead white frog is reaching out to touch a splotch of somethingon the far left)