The shaman decided to curse the man to learn to understand their culture and be part of it. He put the spell on the man in secret using some hair he found left behind , only a string or 2 but it was enough.
Then several teenage tribe members escorted Chris to the cave. The seemed hardly the group that should have been escorting him. The older teens seemed more serious but the younger ones seemed only interested in goofing off or playing short games with each other.
As he was walking to the cave he started to feel odd though. He was sure but it felt like he was slightly shorter, he must have imagined it though. He seemed to be getting slightly younger going into his 20s.
His skin was getting slightly tanned as they walked. These changes were slow and subtle so Chris didn't seem to notice. His clothes getting slightly lose on him. He started to feel very hot all of a sudden , probably due to the jungle temperature. He proceeded to remove his shirt. It was then he noticed that his arms had gained some muscle. Not at all like a body builder but more like lean muscle.
His shoes and socks slipped off as he was walking because his had gotten too small for them. He was confused to the boys kept him going. They seemed to be acting like nothing had happened. He noticed his chest had bulked up a bit too. His pecs had extended and his stomach had become a flat set of 6 pack abs.
"What the hell is going on?!" He exclaimed confused. The boys just seemed to shrug or ask "what?" as if nothing was out of place.
His legs started to shrink in height but also started to gain muscle. Becoming good legs for running or climbing. His pants started to slip off due to them not fitting anymore.
Chris was getting confused and slightly scared but at the same time a small part of his mind was telling him that nothing was out of place. That thought was also reinforced by the way the boys were acting.
His hair started to turn a dark brown possible black color and grew out a bit longer. He was now a older teen perhaps 18 or 19 years old. Also this new voice in his head was getting louder. It felt like it was taking knowledge from him and giving him more useful stuff like how to hunt or climb trees.
All the while he found himself starting to speak and act more full of energy and a lot like the other younger boys. They were almost at the cave now and he was still getting younger. His body began to fill with energy and relaxation at the same time. His current concerns fading as this younger voice took over.
"Damn it what's happening?" He said noticing his voice sounded higher than before. He also noticed he was speaking the native language... and understood it.
He was now about 8 or 9 and very athletic looking for his age. They finally arrived in the cave. There was nothing of money value but that wasn't on his mind anymore. It was a ceremonial cave, for recruiting new members into the tribe.
The boys put him down on the table and painted some of their tribal designs on his chest and arms. They then proceeded to do a ritual that seemed to speed up what was left of his transformation. His muscles bulked up a little more. His boxers which he was in shrunk to his size then morphed into a brown loin cloth like the others. He felt his penis shrink a bit but still good size for his age. He didn't seem to mind it either as his mind began to morph. He was Akiu a member of the tribe. His older brother and a group of his friends to do a manhood ritual . At least that's how he remembered it.
He now knew how to hunt, swing on vines, and climb trees. He forgot all about his past life.
"What are we doing here? Let's go hunt!" He said as the other boys cheered and they left the cave.
The shaman then cursed the whole business to forget about Chris, planning to cast similar spells on any others who might come to take their land.