Harry Potter's Wonderful Wormy Non-Wizarding Challenge
Note: if you want to give this challenge a shot, or have any questions, please don't hesitate to PM me.
Premise: Harry Potter goes on a late night raid on a criminal ring smuggling cursed objects. During a scuffle, he loses his wand and is stabbed through the heart by a ritual dagger and dies. The manner of his death is enough to complete the last ritual it was used in, catapulting him to a space between realities and right in middle of a heated argument between what appears to be a disturbingly possessive Death (complete with scythe) and another powerful being.
Harry, being Harry, foolishly gets between the two just as they appear to be about to come to blows, derailing their argument. The other being introduces themselves as Benevolent Omnipotent Being, or Bob for short. Bob is hoping that Harry's 'infuriating inability to leave a mess alone' will prove useful in keeping his reality from killing itself. He explains that he is bound under a non-interference oath from intervening himself.
Bob indicates he can only use a loophole he found in the rules once before it will be noticed and closed up 'tighter than the collective sphincters of the omni-dimensional bureaucracy,' whatever that means. So he needs Harry's help. After Harry is assured that he will be with him family after his 'job' in Bob's realm is done, he agrees.
Optional plot point: Magic simply does not work in Bob's realm. No magical cores, bending reality, or fancy Latin words for floating feathers. So Bob gifts Harry with the ability to manipulate matter. Two caveats: First, if he increases the mass of an object, it costs energy, while reducing the mass of an objects gives him energy he can store where his wizard's core once was. Second, certain objects are easier than others to give and take mass and energy from. YOU work out the exact details of what those limitations are.
Have fun.