A bit of an out-of-the-box project-- instead of a project about hiding, we explore scratch itself to learn some interesting stuff about the hide block-- and one of the ways that graphic effects can be more than just graphic. The Scratch VM specifically looks for the value of ghost effect, and if it is equal to 100, won't register it as a click. This behavior is also present in 2.0 and 1.4. In most cases, the ghost effect just makes a sprite graphically invisible, but mechanically visible.
