You Thinking it is some sea creature stuck in your clothing you rush into the bathroom and strip down naked. Using the large wall mirror on the wall you look at your rear. To your dismay you have a lump growing on the base of your spine. Did something burrow into my body? you think to yourself. All that changes when the bump changes to a blueish-green color and starts to elongate. The tapered shape resembles the tail of a fish down to the small pectoral fin.
Al you can do is stare.