What's the point in being a parent if you can't scare your kids about toilet snakes?

Our little Megan is a finicky one, especially as relating to all things potty. Her biggest fear is that the toilet is going to back-up, or that when she flushes it will make a weird noise. Every time she goes to the bathroom, before she will sit down she runs through the same drill:

"Is it going to drip out or have a potty problem or have hippos?"

She says it as fast as she can (because sometimes we chime in and finish for her by saying, 'or have hippos?'), and she won't go until we say, "No, it won't." This includes times when she is just on the verge of having an accident.

So, the other night at dinner she hopped up to go to the bathroom (as she does every night, a classic Megan-dinner-stall tactic), and she did her regular thing and yelled from the bathroom, "Is it going to drip out or have a potty problem or have hippos?" Mike couldn't help himself, and yelled back, "or toilet snakes?"

I will do my best to describe what followed, but I am limited by human speech. We heard this strange gasping-big-scream-wind-up noise through which we could make out the words "don't say toilet snake," followed by a very high pitched scream and hysterical crying pleading with us to tell her if the toilet snakes were going to get her. So, I had to get up from my dinner and go in and tell her there were no toilet snakes (or hippos, or potty problems, or dripping-outs), and daddy was just being funny. She calmed down, but was still obviously perturbed when she returned to the table.

Once sitting down, she kept getting a really concerned look and repeating how there weren't any toilet snakes, (dad). Mike said something to her about how he was just teasing her, and she came back with a very angry and firm, "Don't tease me ANY MORE, Dad." Mike just laughed and said she should calm down, and she just said again, "Don't tease me EVER AGAIN." Mike goes, "I can make no such promise." Megan thought that meant he was agreeing with her and so in a very satisfied tone (as in, "I just got THAT job done,") said, "Okay."

So now, before Megan can sit down and go to the bathroom, this is what I hear:

"Is it going to drip out or have a potty problem or have toilet snakes or have hippos?" (I guess they are listed in order of the size of the problem)