The package arrived just as the sun crested the horizon, casting a golden hue over Jerry's sprawling backyard pool. Jerry, a lanky man in his mid-50s with salt-and-pepper hair and a perpetual five-o'clock shadow, signed for the delivery with a mix of excitement and skepticism. The box was unassuming, labeled "DIY Trait Swapper" in bold, futuristic font. He'd ordered it on a whim from some obscure online marketplace after reading wild testimonials about "redefining yourself one trait at a time." Little did he know it would turn his ordinary Thursday into a whirlwind of self-discovery---and confusion.

Teri, the pool service technician, was already hard at work skimming leaves from the water's surface. She was in her early 30s, athletic and sun-kissed, with a no-nonsense ponytail and a toolkit slung over her shoulder. Jerry had hired her company months ago, and she'd become a familiar face, chatting about everything from chlorine levels to the latest celebrity scandals. As he unpacked the device---a sleek, pod-like machine with two chambers connected by glowing panels---he couldn't resist sharing his find.

"Hey, Teri! You gotta see this. It's supposed to let you swap traits with someone else. Like, personalities, bodies, whatever. Want to be my guinea pig? I'll pay you double for the day."

Teri raised an eyebrow, wiping sweat from her brow. "Swap traits? Sounds like sci-fi nonsense. But hey, if you're paying, I'm game. What's the worst that could happen?"

They set up the device on the patio, following the simple instructions: step into the chambers, select traits via the touchscreen interface, and hit "Swap." It hummed to life with a soft whir, the air around it shimmering like heat waves. Jerry suggested starting small. "Let's try names first. Just to test it."

They entered the pods, and with a flash of light, it was done. Jerry blinked, feeling a strange tingle. "I'm... Teri now?" He---no, she?---laughed, but the voice was still his own. No, wait. The name swap was mental; suddenly, he thought of himself as Teri, and she as Jerry. They swapped back immediately, giggling like kids. But the ice was broken. They dove in deeper.