JBMJBM has released Bugs 1.0 for the Mac (http://www.jbmjbm.com/bugs.html). Launch this app and small, realistic looking ants, spiders or lady bugs start “crawling” around your screen — and you can squish ’em. Bugs costs US$2.99, works with Mac OS X 10.6 or higher and is available at the Mac App Store.
There’s also a counter to count how many bugs have been smashed. You can also increase or decrease the number of ants, spiders, or lady bugs on the screen. There’s an option to change the type of bug.