Chromatic

A chromatic scale contains all twelve notes, each a half step apart, with none "extra" or "missing" — unlike a diatonic (seven-note) or pentatonic (five-note) scale, it doesn't favor any degree over another.

A drilling tool more than a melodic one

Precisely because it ranks no note above another, the chromatic scale is rarely used to write a recognizable melody — its main use is warming up and pure velocity work, one finger per consecutive fret, without having to think about which note fits a given key.

The sheet chromatic velocity — one string illustrates exactly that use: a dexterity drill, not a composition tool.