Tracks and displays Thrash procs on creatures.
Findings from my testing suggests that Thrash can only stack up to 2, can proc off hits and be stored on mobs from past encounters.
other Thrash alike abilities in the game:
https://www.wowhead.com/classic/spells?filter=109;19;0
* Some monsters have a “Thrash” mechanic and can proc multiple attacks against players in a very short duration.
Note: Most of these monsters can also “store” these procs and unleash them all several seconds later.
An example of this is the Princess Theradras encounter in Maraudon.
The Princess will store her attacks if kited and can land several attacks instantly when she catches up to her target. This behavior is consistent with the reference client