The substance you're referring to only exists elsewhere in the universe.
"The point at which a substance exists simultaneously as a solid, liquid, and a gas."
Well, every substance can exist either as a liquid or a gas.
If this substance does exist, does it have a name?
For example: a substance exists that blackens the fingers of those who touch it.
Instead, substance describes something that is primary and can exist on its own.
Sometimes urine screening is done to make sure no substances exist in the subject's body that might interfere with sleep.
Most scientists say that the small nuclear weapons, as well as the substance allegedly used to make them, do not exist.
"Just having shown that this substance can exist even temporarily is a gigantic achievement," he said.
What is lost is a "gut feel" that these substances really exist.