This is an aurabar type aura.
*with huge help from asakawa over at the WA Discord*
Progress bar which changes it's color if it won't be possible to refresh Frenzy due to GCD or Barbed Shot CD. It's a simple red progress bar with stack indicator. The whole bar turns into a frustrating purple if the remaining duration of Frenzy is shorter than the current GCD or the remaining CD of Barbed Shot.
Changelog
20180720 - updated for BfA
20170522 - slightly reworked coloring