Mirumok Watcher unkillable but required for the knowledge to get 1 energy. The Mirumok Watchers are the trees that used to be killable but made unkillable in a recent patch. Now, there's no way to get the knowledge.
What is your AP, I have that knowledge
It's not unkilleable. After all the spawn weave it becomes attackable.
It is unkillable during the time it spawns mobs. After it's done spawning, you can easily kill it. :)
shoulda just got S knowledge when it was solo zone few years ago
/troll
anyway, what others said.