https://naruto.fandom.com/wiki/Natural_Energy
"Natural energy circulates all throughout the world, but it is usually imperceptible."
Life Fibers exist in virtually every living thing on earth and everywhere on Earth but doesnt do things most of the time due to being dormant.
"In order to use senjutsu, one must first learn to sense the natural energy in their surroundings and draw it into their body, which requires becoming "one with nature" by remaining perfectly still. To control the natural energy they absorb, the user must balance it with their own physical and spiritual energies, which together make up chakra, in order to create senjutsu chakra."
Very few people are capable of withstanding life fiber energy, requiring years of physical and spiritual training in order to not be consumed by a single strand of it. Satsuki herself had to go through multiple spiritual cleansings and chakra alignments in order to properly wear her kamui.
"If this balance contains too little natural energy, senjutsu cannot be used, but too much makes the user turn to stone; in the case of humans, they first turn into animals before petrifying. This process can be reversed if the absorbed natural energy is expelled before the transformation is complete, and Fukasaku wields a staff capable of beating the natural energy out of a person on contact."
Life Fiber enrgy in imbalanced proportions on a normal person will turn them into monsters and/or outright kill them instantly. This can be undone through pressure point application that expels the life fiber energy from a person while also removing the life fibers from their body, and weapons exist that expel and nullify life fiber energy such as Tailor Needles.
"Members of Jügo's clan possess special bodies that can absorb natural energy and undergo transformations. However, this power also causes them to go berserk without warning. Through his research, Orochimaru developed an enzyme from Jügo's bodily fluids that is capable of inducing similar transformations in other shinobi. He is able to apply this power to others, alongside his own senjutsu chakra, in the form of cursed seals."
Ryuko and the experiments performed on her by Ragyo. Also Nui. Technically the Honouiji sewing club too as that is basically describing anyone with a 3-Star uniform.
"The Ten-Tails' vast power is described as feeling like natural energy itself; as such, it can only be sensed by those capable of using senjutsu. The beast is capable of manipulating natural energy, and by using its enormous chakra to disturb the natural energy in its surroundings, it can cause a series of natural disasters to occur. Natural energy is key to defeating the Ten-Tails' jinchüriki, whose body is immune to ninjutsu; Naruto Uzumaki describes this as fighting natural energy with natural energy."
Life Fiber energy is immune to virtually anything less that the power produced by another Life Fiber energy user and only weapons that are made from life fibers or directly nullify life fiber energy are capable of harming them.
"God Trees grow by absorbing their planet's natural energy, draining power from the environment and its inhabitants alike until the planet becomes a desolate world devoid of any life."
The Cocoon Genesis Sphere in a nutshell