Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Ruined our wall

While I wasn't surprised that this product didn't help our dogs (I assumed it was probably something that would work on some dogs & not others) - I was not happy that the plug-in caused the latex paint on the wall above it to bubble. It worked it's way through multiple layers of paint, so we were forced to strip the whole wall rather than just repaint the affected area.