Spoilers

This mod adds large sphere of negative weight and powered sphere of negative weight and changes how small sphere of negative weight behaves.
A large sphere normally weighs -100#. Wish for one with helado_Antiweight Orbs_Large Sphere of Negative Weight.
A powered sphere weighs -25# when turned on. Wish for a powered sphere of negative weight with helado_Antiweight Orbs_Powered Sphere of Negative Weight.

Floating Away

Any sphere of negative weight will try to float away if able.
If under open sky (as opposed to underground or otherwise in an indoor zone), any sphere or holder of a sphere that weighs a negative amount will try to move up one stratum each turn.
A creature's weight is not visible in the UI, but it depends, among other things, on their strength and how much they're holding. You will have to guess what your safe threshold is for carrying negative weight.
If an object floats more than 10 strata aboveground, it floats off into space and is considered permanently gone.
Dropping some negative weight can help if you find yourself floating off, but be careful doing so once you're more than a single stratum aboveground, because you will take fall damage once gravity reasserts itself.
Yes, you can use this to shortcut one of the game's quest locations. I'm not going to stop you if you want to do that.

The large spheres (and only the large spheres) are unstable and may explode.
There is a very small chance each turn. There is a less small chance whenever they take damage (no matter how much damage).
The explosion is less powerful than a neutron flux explosion, but still powerful.
The sphere itself is instantly destroyed but anything else caught in the explosion can survive with enough HP.

The powered spheres (and only the powered spheres) consume charge to work. Each one has an energy cell slot.
The energy cell contributes (positively) to the weight of the sphere, whether it's working or not.