After Ty finished breakfast he found himself stuck with a huge boner and sudden primal instincts. For his next change, Ty considered he might need privacy so went outside and traveled behind his house. “Fuck I am horny!” Ty said rubbing his hairy body.
“Ty, what’s happening to you and why doesn’t anyone notice?” Ty then turned to the direction of the voice and found it was Dustin who had followed him.
“Well little brother, I’m...I’m,” Ty struggled to find the words, “I’m turning into a caveman.” Ty finished confidently
“A caveman?!” Dustin doubted.
“Yeah I caught a bug called Degenitis Hominus which devolves only humans who come in contact with it into Neanderthals.” Suddenly Ty started to slouch and his boxers finally exploded under the pressure of a caveman’s fully grown genital.
“T-t-ty are you okay?” Dustin sputtered scared for his life and as soon as Ty looked up, Dustin knew Ty was gone. Dustin began to run away from Ty but it was all for nothing because Ty was a primordial beast in its prime in peak physique. Once he was close enough Ty pounced onto Dustin and tore his pants and underwear off revealing an already hairy as. “It started already.” Caveman Ty stated as he plunged his frothing erect junk into Dustin’s tight muscular and hairy ass.