I tried to shove both images aside. But as I felt the morph begin, I thought, I'm coming to

save you, Mom. And I also thought, I'm coming to destroy you, Visser One.

The morph began differently than it had during my partial morph in the pool. This time it was my skin that changed first.

Dolphins have skin like gray rubber or latex. Sharks have skin like fine-grained sandpaper. Shark skin can leave human skin bloody just by rubbing against it. It's actually made up of millions of denticles.

Those are tiny, mutated teeth. Sharks are coated with tiny teeth.

As I watched, my tanned arms turned gray. My legs turned gray. My chest and shoulders, all gray.

My feet were twisting together weirdly, as if they were a pair of straws I was braiding. When a wave rolled into me, I lost balance and went backward into the water.

My hand scraped along the bottom. When I looked at it, I realized I'd cut myself on a shell. A few drops of my own blood dribbled into the saltwater.

But I had other things to worry about. Besides, when I demorphed, the cut would be gone.

When I tried to stand back up, I realized my legs were gone. I had a tail now, made of gracefully swooping triangles.

Everything on a shark is triangles. Two elongated, joined triangles make the tail. Triangles form the dorsal fins. And hard white serrated triangles fill the mouth with the weapons of destruction.

I used my arms to windmill the water and keep my head up. In flashes between waves I saw the others. A hideous Rachel, with a shark mouth and blond hair; an awesome Ax, with Andalite stalk eyes rising from the bulging hammer's head; Tobias, with feathers melting into gray sandpaper. Not even Cassie could make this morph pretty.

I felt the teeth growing, replacing my own pathetic human teeth. And at the same time, my eyes were moving. They were rotating out to the sides of my head. I lost the ability to focus and kept trying to aim my eyes, to see in three dimensions like I can normally. But my eyes were moving too fast, too far. All I could see was a blur of water and eerie faces.

The hammerhead didn't grow out of the side of my head. It grew out of the front. Like pillars of flesh were growing beneath my eyeballs, then taking those eyes out to the side.

My arms shriveled and became sharp fins. I was entirely underwater now.

Just in time, my lungs collapsed into nothing and slits like open wounds formed where my neck had been.

I had gills. And shark's teeth. And I had shark's eyes.

But I still had not felt the shark's mind. Not until I was completely in the water and began to move. Only then did I feel the shark's mind, its instincts, come bubbling up through my own human awareness.

It was the movement that set it off. See, sharks cannot be still. If a shark stops moving, he dies. A shark is movement. Restless, relentless, eternal movement.

I felt my fear leave me.

I felt my anger leave as well.

My every emotion and feeling simply lifted away. And I was glad. Because now I was clear. Now I saw the world with perfect simplicity. Perfect understanding.

The world, you see, is nothing but prey. And I was nothing but hunger.

There was nothing else. No mother or father, no fear or joy, no worry.

Hunger. Prey. Hunger. Prey.

I turned away from the shore and swam out to sea. And then, I stopped.

The last vestiges of my human mind were swept aside.

The shark sensed blood.

Sharks had been swimming Earth's oceans for hundreds of millions of years already when the ancestors of Homo sapiens were still trying to figure out how to peel a banana.

People will tell you, "Oh, you don't need to be afraid of sharks. They have more reason to fear humans than humans have to fear sharks."

True. Humans kill far more sharks than sharks kill humans. Will that fact make you feel any better if a shark chomps you in two at the waist?

Probably not.

Sharks are killing machines. Mostly they kill fish. In some parts of the world they kill seals. They kill dolphins. They kill whales, when they can manage it. And they kill humans. At least some species do: the great white, the tiger shark . . . and the hammerhead.

This was the killing machine I had become. Utterly without fear. Utterly without emotion. A mind with no room for anything else but killing.

There was nothing playful, like you'd find with a lion. Nothing in the shark that cared about family or children. No sense of belonging. Just a solitary creature of sharp, cutting triangles. A restless, ever-moving thing, ever questing after blood.

A mind as cold, as sharp, as deadly as a polished-steel knife blade.

That was the mind that gathered my confused human consciousness up and swept it along in the endless search for something to kill and eat.

The shark turned toward the scent of blood. My long tail pushed lazily at the water. My hammerhead worked like a diving plane to let me turn this way and that. My vision was surprisingly good. Almost as good as human vision.

I could hear. And I could feel other senses that were unlike anything human. When fish passed close by, I felt a tingling from their electrical current. And at some deep, hard-to-grasp level, I realized I could sense the very magnetic field of planet Earth. I knew north and south without knowing the words.

But mostly, I could smell. I could smell the water as I sucked it in, relentlessly sampling. And right now, I could smell blood.

I was aware of the others nearby. I knew they were sharks like me. But I didn't care. I was on the trail of blood.

I followed the scent of the blood. No more than a few drops of blood, a thin, wispy trail diluted in billions of gallons of surging seawater, but I smelled it.

I followed the scent through the water. If the scent was stronger in my left nostril, I veered left. If it was stronger on my right, I veered right. It would lead me to prey. It would lead me to food. The blood trail had come from very close by! I could sense it, and a cold excitement seized me.

Blood! A wounded animal! Prey!

But as I turned and turned again, circling back toward more shallow water, I became frustrated. Where was it? Where was the bleeding creature? Where was my prey?

The others circled nearby. One of them brushed against me, sandpaper on sandpaper. They were seeking it, too. The bleeding prey whose scent filled our heads.

Where was it?

The shark brain was confused, uncertain. And in that moment of confusion and uncertainty, the