The pair went to the backyard and Darren handed him the emitter with a gleaming grin. "Walk around," he said pointing in the direction.
Jeff headed off in the pointed direction confused. As he got 20 feet from the mansion something shimmered into existence around 40 feet from him. As he approached it, it grew along the ground and as he reached it, he identified asphalt.
Halfway through tracing the path, Jeff realized he was summoning in a go-cart path! He looked back at Darren, now matching his glee. As he found the starting position on the track, two carts materialized, one red, one blue, and Jeff ran the rest of the way around as Darren began walking to the carts.
Jeff returned out of breath, handing back the emitter. "Thought you... were gonna... change me." Jeff panted, "Wouldn't mind some... extra stamina... bout now."
"I did." Darren chuckled, "But I thought it would be more engaging if you got to unlock the new skills, and less jarring if you grew into your stronger body rather than a 'poof, you don't recognize yourself in the mirror' kind of thing." Jeff shrugged in response, not knowing what else to say.
Jeff watched Darren start the machine's engine, gaining a little mechanical knowledge across a multitude of machines, repeating the steps on his go-cart. A moment later, they were racing down the track.
Eventually, the carts ran out of gas. Though a few button presses from the Chronivac could have refilled them, Darren asked what Jeff wanted for his next activity.
"Aww, we're done? You're just upset 'cause I beat you!" Jeff jested, surprised his voice had dropped and was sounding close to that of a man rather than a teen.
"Ha! The carts are the same except for color. Gain another 75 lbs, then we can see who wins." Jeff was taken aback by the sudden realization that he had nothing to do with his winning.
Darren saw the disappointment on Jeff's face, "Cheer up, you should officially be one of the best drivers in the world now."
"Huh?"
"That should have unlocked the 'driving ability' skill across the board. From racecars to helicopters, to cruise ships..." Darren smirked.
Jeff paused accessing new memories of learning that didn't have any context, but making the operation of all sorts of vehicles familiar to him. "Cranes, bulldozers, semis... Tanks? Why would I need to know how to drive and operate tanks?!"
"It was a package deal, plus, you never know when it might come in handy, and it doesn't hurt to know," Darren smirked back.
"So, can we explore the jungle forest now?" Jeff's eyes shimmered with anticipation.
"Uh, that's probably a tomorrow activity since driving skills won't help much with defending yourself in a dense jungle."
"That would give me survival skills though, right?"
Darren eyed Jeff carefully looking Jeff up and down. "Sure, but you should be able to defend yourself before going in. Jungle cats are powerful and can sneak up on you. You've just hit your late teens; it'll be better if you were strong enough to carry your own weight first. So tomorrow then."
"How do I unlock my strength? Should we conjure in some weights?" Jeff eyed the Chronivac.
"You're going to be strong, body training will give you skills related to human anatomy and biology, but Jeff, a weight room would be the most boring way to unlock those skills!" Darren chuckled as he entered some commands into the device, and a climbing wall suddenly towered above them.
Jeff smiled as he recognized what was suddenly casting a shadow over him. Their clothes suddenly constricted as climbing gear appeared over them and attached to the cable at the top of the wall. Jeff looked at his body, realizing for the first time that he was starting to get hairy, and he needed to adjust his crotch area because his penis was bigger than genetics dictated it would be.
After two tries Darren was done with the activity, but Jeff continued again and again for half an hour before admitting he was exhausted. A few button presses and the wall and gear faded from existence. Darren pressed a few more buttons and a full-length mirror appeared, "Jeff, I think you're probably 18 now... an adult." He pressed a few more buttons and a small card popped into existence, Darren handed it to Jeff.
"A driver's license?"
"Yeah, if we ever go into society, it'd be weird for you not to have one."
Jeff looked at the photo taking note of the height, weight, and birthday listed. He looked in the mirror and saw that his face looked different, not just because of his neck becoming thicker or the denser facial hair becoming visible. Something about his jaw muscles and everything just came together to be different enough; he really looked older. He was starting to look athletic despite his hobby being video games.
Darren punched a few buttons on the device and a wooden picnic table appeared complete with meal. burgers and hot dogs with all the toppings were pulled into reality and after smelling the food, Jeff realized he was ravenous.