guys i will be posting whatever i have come across for Grobbulus (25 man) Fee; free to corect me if i am worng Thank you

Raid Setup

25 Man
2 tanks, 3-5 healers, and the rest should be a mix of ranged and melee DPS. Ranged are generally better in this fight because they stand clear of the Poison Clouds left by the boss.
Boss Abilities
25 Man - 9 600 000 HP
Melee hit - Approximately 10 000 physical damage.

10 Man - 2 900 000 HP
Melee hit - Approximately 6 000 physical damage.

Poison Cloud - These green smoke circles are placed on the floor at Grobbulus' current location every 15-20 seconds. They slowly grow for around 1 yard a second until they are approximately 30 yards in diameter. Anyone inside one of these clouds takes 4250 damage per second (2000 damage per second in 10 man).

Mutating Injection - The second way that Grobbulus places Poison Clouds in the room. He will target a random player in the raid and place this debuff on them. After 10 seconds, or if the debuff is removed, it will deal 8075-8925 damage to everyone within 10 yards (including the player with the debuff) and place a Poison Cloud on the floor at the affected player's current location. This ability is used slowly at the start of the fight (around once every 20 seconds) and more rapidly near the end (around every 8-10 seconds).

Slime Spray - A frontal cone shaped AoE attack which deals 11 875 - 13 125 damage to anyone in front of the boss (6 300 - 7 300 in 10 man). Anyone hit by this will also spawn a Fallout Slime mob. This ability has no cooldown, and is used whenever Grobbulus "feels" like it. It has a 45 yard range.

Fallout Slime - 190 000 HP. This hits for 5000 and has a passive AoE which constantly hits everyone within 10 yards for 2000 damage per 2 seconds. This is a Taunt-able mob which can be and needs to be picked up without moving in front of the boss.

Berserk - The hard wipe ability of the boss. After 6 Minutes he will go Berserk increasing his damage by 1000%.

The Pull
Grobbulus patrols up and down a ramp and balcony into the main fight room. When he walks down the ramp, have your main tank run in and pick him up or, have a hunter Misdirect him on to the main tank.

The Fight
The fight is relatively simple as long as people remain aware. The main tank will be tanking the boss facing away from the raid and moving him around the edge of the room. All ranged DPS and healers will remain in the middle of the room. Melee DPS will stay behind the boss at ALL times to avoid multiple fallout slimes spawning from Slime Spray.

Every 15-20 seconds a Poison Cloud will spawn under Grobbulus. When this happens, the main tank will need to move several yards (10-15 yards) until the next one occurs and the same thing happens again.

Grobbulus stomping on his oppositionOccasionally Grobbulus will use Slime Spray. If your raid is positioned correctly, only the main tank will get hit and one Fallout Slime will spawn. When the Fallout Slime spawns, your off tank needs to pick it up quickly with a ranged pull, or you can have a hunter Misdirect it on to the off tank. the off tank then needs to move out to the side (towards the ranged DPS and healers). When this happens, all DPS, both ranged and melee, need to switch DPS target to the Fallout Slime and kill it as quickly as possible. Although melee DPS will take some damage from the Fallout Slime's aura, it is not very high and you should be ab;e to heal through it no problem. When not tanking a Fallout Slime, the off tank can DPS with the melee.

The final issue to deal with is the Mutating Injection. When a player is infected with this they need to run quickly to the back of the room and onto the ramp and wait for the debuff to run out. Don't be afraid to run a long way up the ramp (although not shown on the diagram it is a very large area). Avoid any Poison Clouds or other players who may have the debuff; the large area gives you plenty of room to do this. Mutating Injection must not be dispelled or removed under any circumstances otherwise all players close to the infected player will take huge damage.

Main Tank: Build as much threat as possible to allow your DPS to go all out. Stay aware of the Poison Clouds and make sure the boss is facing away from the raid at all times.

Other Tanks: Wait for the Fallout Slimes to spawn and pick them up as soon as they do.

Healers: Assign around 4 healers to the main tank (2 healers in 10 man), and put one healer on the off tank and the rest of the raid. Just keep people topped off in case someone dispels a Mutating Injection.

Ranged DPS: Push out as much DPS as you can without over-aggroing the main tank. Switch to the Fallout Slimes when they spawn.

Melee DPS: Push out as much DPS as you can without over-aggroing the main tank. Switch to the Fallout Slimes when they spawn. Stay behind Grobbulus at all times.

Miscellaneous Tips
Never allow a Mutating Injection to finish or be dispelled near other players.