A simple act of will sees you vanish from your house and appear in your girlfriend Imogen's.
She's pacing back and forth naked, with the curtains drawn, a habit of hers you'd never known before but which leaves you, being all-knowing now, completely unsurprised. Going up behind her, you cover her eyes with your hands. "Guess who!"
She whirls. "John? How'd you get in?" She doesn't cover up, in part because you've seen her naked before and in part because you're influencing her to stay that way.
"Oh, I teleported in."
"Teleported?"
"Yeah, simple stuff. I'm omnipotent now, so I can do basically anything I want."
"Anything?"
"Anything at all. I could make you the richest person on the planet with a snap of my fingers. I could turn that sexist asshole Darren into a woman with a thought. I could make your best friend Fannie fall deeply in love with you. Or whatever else you care to name."
"Could you make me omnipotent?"
"I could, but I want to get used to my powers first. One inexperienced god might bode ill enough for the universe; two just might destroy it."
"Well, why not just give yourself the experience?"
"Of course!" And with a thought you know exactly how to use your infinite power to do anything you want. "Just for that, I'm going to give you your dream body--or should I say bodies?"
And with that Imogen gains a second body, identical to her first. Effortless exercises of will give each of her mouths sixteen long, prehensile tongues, while her hair becomes the rich brunette she has always desired, becoming thick and lustrous, growing down to her ankles. Being 10' tall is another important part of her fantasy, as are the four titanic tits you give her on each body. The eight pairs of arms come in next, along with the very athletic look, allowing her not to have need of any support for her breasts. A tiny waist leaves her looking as if she should simply snap in two, while her hair gets longer to compensate for having to go over her massive butt. Each body gains a second pussy, and you warp reality to make her vaginas larger inside than out. Each pussy gains four tongues, perfect for providing additional pleasure to the two long cocks each body grows--on one body, situated above her cunts, on the other, below, so that she can easily slip in when her normally 20" dicks extend to their full three feet when erect.
Imogen begins feeling herself up. "This is incredible! You really are all-powerful, aren't you?"
"I am. Anything else you want--other than becoming all-powerful. I'll have to think on that one."
"Anything else? Well, I want to be bigger--not unreasonably bigger, just a bit. Maybe 15' even? And a few more things..."
"No problem," you say as she finishes her list.
As she requested, you make her fifteen feet tall, and give her four more pairs of arms. Her mouths gain twenty more tongues each, and her hair, while still reaching to her ankles, is also in an elaborate hairdo. Her breasts sit in three rows of two, and each is larger than the four you had given her combined--that these fit on her chest, that she can still see, and that she can reach around to play with her extremely sensitive nipples, even though each of her previous four had been by far the largest in the world is a testament to your infinite power. Her crotches now sport three pussies each, each one with six tongues, and each with its own 5' dick. As soon as they grow in their length doubles as Imogen wills them erect. Her body becomes very muscular, though her muscles enhance her feminine form, and her ass becomes gigantic.
"And the other change?" she asks.
"Yes, you can walk about naked wherever you want, and even perform lewdly sexual acts in public, at least with yourself or consenting adults."
"Thanks, John. Just two more things: first, will I ever see you again, you being all-powerful and what now?"
"I can do anything, so I can come see you whenever I want." You appear next to yourself. "I can even travel through time to do it!" The body that had not just spoken vanishes. "See, I just went back a few seconds. It would have been just as easy to go back a few minutes, days, months, years, millennia, whatever."
"Cool! And second, could you send me somewhere nice and public? I feel like showing off now that it's fine for me to do so."
"Anywhere in particular? Oh, and you're invulnerable to basically everything. Heat, cold, rough sidewalks, nasty diseases, whatever it is, it can't hurt you."
"Just somewhere open and outside, and the busier the better."
You find it no harder than anything else you've done to make Imogen vanish from her house and reappear in a bustling town square.
You decide to go out yourself, and alter your body as a disguise. A simple thought makes you a foot taller and mostly female, with butt-length blonde hair, pumpkin-sized boobs straining a midriff-baring strapless top and showing more than a foot of cleavage above and below, and a deep, juicy pussy making a camel toe in your tight shorts that show off your shaven legs. Six inch heels, a bulbous ass, an athletic build and a radiant face complete the look, and you vanish from your girlfriend's home to play with your powers elsewhere.