Actually saw a cooking tip online about this very thing. Creamy soups can bubble over like crazy if you don't watch them. @jake_torres68's story about scraping chowder off the microwave walls hits way too close to home. The tip said to heat in short bursts and stir a lot (which is annoying but worth it). Now I'm paranoid every time I warm up my tomato soup.
Was it a creamy soup? I turned my chowder into a science project last week. Forgot to stir it halfway and had to scrape dried soup off the microwave walls for fifteen minutes. Now my lunch smells like regret and burnt dairy.