Not sure why I'm being asked how much fun this toy is, as it's not a toy!!! A vanishing marker pen I bought to use for marking quilting lines on light coloured fabric. It worked quite well although it behaved a little like a "nearly-out-of-ink-felt-tip" while drawing with it and the line vanished rather too quickly... I needed to go over lines several times as, frequently, when I started to sew a short length (say, along a 4" line I'd just marked), the far end of the line had almost vanished before I reached it! Having said that, it was a useful tool, the line more accurate than can be obtained with a chalk pencil (which blunts quickly and inevitably gives a wider line) and I would use it again. It showed well against white fabric, less well against blue patterned fabric; you'd need a different, light colour for use on darker fabrics.