Once upon a time, there a young named Nethanel, but he preferred his spirit Ginger Bat. Ginger Bat loved all animals, great and small, and couldn't understand why people so regularly killed them for fur, and food, couldn't they understand the poor creatures they were slaughtering to fill their bellies? Or to keep themselves warm in winter? Ginger Bat tried to spread the message, but was either laughed at, or banned from public forums for being "too argumentative and confrontational" or so they claimed.
Ginger Bat however, was not stupid, nor was he uneducated. He was able to get a job as a intern at a genetics lab, finding way to hybridize different species' DNA. Ginger Bat knew what he had to do. On the night the compound was complete, he 'borrowed' a vial and went to the local zoo... hid in the ladies' bathroom until after closing hours, and went straight to the lions' enclosure.
Using the dart gun he'd bought, he fired at the lion. In response, the lion grew thumbs, its hips and spine grew to walk upright, and became humanoid in shape.
Without hesitation, Ginger Bat climbed over the fence and said, "Hello, my name is Ginger Bat, what's yours? Don't be afraid, I'm your friend-" That's as far as Ginger Bat got before the new humanoid lion mauled him to death. It seemed Ginger Bat had forgotten he was using mad science, not magic... and that intelligence, complex communication, empathy, and morality, were all learned traits, and a new shaped brain and vocal cords would not automatically grant these, nor would the lion then spontaneous understand everything it had ever heard or understood before them.
As for the lion, it then climbed over the fence, and proceeded to reek havoc in the zoo on the prey animals, until it was gunned down the next morning, which resulted in a massive cover up, and the lion's corpse being confiscated. Thankfully Ginger Bat had not taken anything else with him from the lab, and he had only the one dose he could steal, and no way to trace what had created the mutant lion back to them. But to be on the safe side, the genetics lab had closed up shop and had moved overseas to continue their mad science elsewhere. Maybe Doctor Moreau had been on the right track with using islands...