Verrrry Interesting...... Funny, a co-worker told me today about coming home to a rotten egg smell in their practically brand new house. Then they remembered something their builder had told them about flushing out the drains (basement and garage) every 4 months to avoid just such a smell. They had forgotten to do it since the summer, hence, the smell. I wonder if there's any chance you have the same problem?
Meanwhile, glad to hear Geela is OK, and that Sammy was NOT skunked!