The Elusive case of the "Oh No!"

There is this thing called the "Oh No!"  that has shown up a couple of times while our one and half yr. old has taken her baths.
The water first starts out warm and bubbly and tea parties and much splashing occurs with great gusto.  Then, like a party spoiler, something brown shows up and begins to float around in the once tranquil waters of super fun bath time.
Baby girl spots the intruder and screams, "Oh No!"  She panics, tries to climb out of the tub, screaming and looking over her shoulder.
 I try to help, but she is now clawing at me, tears rolling, shear terror on her face.
Yes, the "Jaws" theme song is playing somewhere in the house, I am sure of it.
This brown, nasty thing we call the "Oh No" has made the last two weeks of bath time very hard for said baby.  We now have to stand together while filling the tub.  Mommy has to swish the water around, pull everything out, and no bubbles are allowed. (It's hard to spot the intruder under bubbles) 
Hopefully, a few "safe" bath times will bring back the pleasure of soaking and tea parties for the baby. 
As long as the awful "Oh No"  keeps it's distance.