Your own raid boss idea

[Tsuki]

QUICK MAKE A RAID BOSS GOGOGO (also obligatory "blizz you can use any part of this as you wish idgaf actually it'd be really freaken cool if you did you don't even need to credit me cause lol that'd be silly stuff goes here)

Stomachfoot, the colossus snail.
525million HP.

The fight takes place in a large circular sewer, the snail itself takes up the entire corridor, so you can't get around it. THe battle starts with it in it's shell, sleeping, and when aggroed, it slowly chases after you. (about 15% of regular running speed)

Oozing Trail: (constant effect)
Stomachfoot leaves behind a trail of corrosive slime, instantly killing anyone who touches it.

Withdraw: (CD of 1 minute)
Stomachfoot withdraws into it's shell, reducing all damage taken by 75%, and healing itself for 2% of it's health every 5 seconds. This effect lasts for 20 seconds, or until it takes 1 million damage total.

Cracked Shell: (In effect after Withdraw is broken)
Stomachfoot takes 25% more damage for 20 seconds.

Revitalized: (In effect after Withdraw ends, and was not broken)
Stomachfoot moves at double speed for 20 seconds.

ADDS:
-Giant Sewer Spider 1605K HP (spawns when players approach a Webbed Pipe (There are 6 in total))

Venomous sting: (melee range) (5 second cooldown)
Giant Sewer Spider deals 20k damage to target player, and poisons them for 10k damage per second for 10 seconds.

Webbing: (Ranged) (10 second cooldown)
Giant Sewer Spider binds a random player in webbing, preventing them from moving until the webbing is destroyed. (Webbing has 169k hp)

-Sewer Rat 17k hp (spawns in groups of 20 when players approach an Infested Pipe (There are 12 in total))

Swarm: (12 second cooldown, shared by all active sewer rats)
A Sewer rat will cry out, causing all nearby sewer rats to attack it's current target.

Latch on: (passive)
Targets that sewer rats are attacking are slowed by 5%. This effect stacks.

-Sticky Ooze 14million HP (Spawns when players aproach Leaking Pipe. 2 in total)

Sticky, Toxic Ooze: passive
Players that are within 5 yards of Sticky Ooze are slowed by 75% and take 50k damage per second.



The enrage will simply be when a full lap is taken, and there is no safe ground to stand on, as the entire circle will be covered in Stomachfoot's instant killing slime-trail. It would take about 6 minutes for a single lap to be taken (4 in heroic, 8 in LFR), assuming Stomachfoot is never effected by Revitalize.

While in the room, you'll be under the buff "Approaching Death", which allows all spells to be cast while moving with no penalty.
The general strategy would be for ranged to attack the boss (it has no aggro chart, it simply moves in a set path), melee to kill adds, and tanks to pick up adds and tank them.