Sharpie's Liquid Pencil
For the longest I can remember, the sharpie was the marker that was banned in school. It was that singular marker that left permanent graffiti scattered throughout school grounds and teachers were determined that you were Sharpie-less. That might be changing now due to Sharpie's latest magical liquid pencil that allows you to erase your ink within three days, otherwise like its predecessor, the ink will remain permanent once again. It's great that Sharpie finally upgraded their product.
I suppose now you could temporarily actually design your Lamborghini Gallardo on your offtime. Just be sure to erase it before the third day or your car might look like this: