the glowing disk blue parts turn to red

It open a Big Orange portal and a blue glowing in the middle

Also this music will play

https://youtu.be/yMo1UJVH7sw

and it will spawn random special zombies and creatures 

(at random times and spam)

margwa

parasite

hellhound

panzer soldat (bo2 version and bo3 version)

spider 

thrasher

nova six crawler

Furies

Tormentors

Jolting Jack

Mimic

Jumping Jack

Russian Mangler Soldier

Stokers

Blightfather

Assassin

Bombers

Pests

brute

sentinels

also normal zombies from the past and the future (ww2,waw, black ops 1 2 3 4, infinite warfare and cold war zombies)

WW2 and black ops 1 2 3 4 and cold war special zombies

it will continue spawning them forever, you need to find  a way to fix the summoning key to order to close the portal  and stopping it from spawning special zombies and creatures