You are not alone, my friend! I use and love the FRIXION markers that disappear when you press them (the lines reappear in very cold -- refrigerator-like conditions, though; but that's not a worry.) Anyway, I was also marking a quilting pattern on a quilt top. The Frixion pen was right next to a permanent marker and, you guessed it, I inadvertently picked up the wrong one! YIKES! The good thing, however, is I drew on only one block. Whew! That was a lesson WELL learned!