King in the mist is invulnerable and does not attack or move, totem is untargetable as well

i am playing an pathfinder toxic rain ballista build in an lvl 73 strand, and i found the king in the mist which i got to around 70% hp and then he moved to the side and became invulnerable and static, the totem in the middle does not seem to have an hp bar and it is untargetable, there are no other mobs around the boss area
https://imgur.com/lpmDvsr

reference number: 427,534,994