Hillarzu the First

Hillarzu the First is a crown-level fungus that can be encountered among other in the  area.

Hillarzu is a very rare spawn. Seems that to spawn him you need to kill some :
 * => 99.75% / 0.25%
 * => 50% / 50%
 * => 80% / 20%
 * When slain, he will always respawn as a.

(From: http://rom.onlinewelten.com/articles,id397,0,wechselbaelger.html#HeulendeBerge)