Ty splashed clumsily out of the water and drug himself up onto the river bank. He froze in fear as he felt himself changing: weed had never done this before! His bones reshaped and he tore his clothes off frantically as black fur grew in. He tripled in size to over 500 pounds and went from six to eight feet tall. He grew claws and fangs, his body buffing out in muscle covered by a thick layer of fat and a heavy fur coat. Within minutes, he was a huge anthro black bear.
"Ty?" he heard a voice coming from the woods. "Are you okay?"
It was Jake, a 14-year-old scout from his troop. He was always following him around, trying to imitate him. He tried to keep his worse habits away from the kid and hoped he hadn't seen him smoking. He tried speaking to him and found he still could.
"Jake, stay back," he warned. "I don't know what's happening to me. Go get Mr. Johnson!"
Jake ignored him, though, and came closer. "Your a bear now, that's so cool! What's it feel like? Can I pet you? Are you gonna live in the wild—"
The boy was so excited he wouldn't listen. Then, suddenly, Tyler was overcome with the urge to mate. Already mentally weakened from the pot and the transformation, he couldn't stop himself from lifting the boy up and using a claw to slice off his clothes.
"Ah, Ty, what are you doing?!"
Ignoring him, Tyler covered the boy's mouth with one huge paw and spread his ass with the other. Jake tried to scream, but the sound was almost inaudible. Tyler entered him and began bouncing him up and down. The virus had taken over his mind and was working to spread itself through sexual contact.
Jake began crying as his anal virginity was taken: he was scared and hurt. Then he felt himself being filled by Tyler's hot load of bear seed and stopped struggling. He was also changing, sprouting fur, fangs, claws, and a long tail. His face was covered by a black mask pattern while grey fur and a black striped tail took the rest. He didn't grow, but he became much stronger and filled with lust. He began humping back against Tyler, coaxing out another load which was immediately absorbed into his body. The second shot completed his transformation and he turned around to kiss Tyler before they separated, looking for new hosts to join them.