The Gizmo eraser was a heartbreaking thing to own. Like all other character-shaped erasers that kids insisted they needed at the start of the school year, there was an intense emotional struggle as to whether or not we could actually use them to erase stuff. If we did, we'd gradually wear down our favorite characters, making them look like disfigured amputees. It wasn't pretty. Fortunately, most kids didn't care about their grammar or math mistakes enough to go back and fix errors.
The package demands that you never feed them after midnight, and the way it's worded, it's pretty tough to figure out if they mean real mogwais or just the mogwai erasers. I'm not taking any chances. The last thing I need right now is for my school supplies to eat me. I've injured myself well and good enough attempting to master scissors and staplers - why make a move that'd shift the balance of power once and for all?