Professor Putricide

Putricide is also a good Resto druid fight. It's a 3 phases boss : phase 1 and 2 are a permanent switch between Green ooze, boss, Red ooze, boss, Green ooze, .... In phase 3 raid damages are growing as the tanks get debuffed, otherwise it's a tank and spank phase.

In phase 1 keep hots up on the tank, use Regrowth and Rejuvenation on the player with the Plague. Remember to use your Barkskin if you get the plague. Especially hot the abomination with Rejuvenation and Wild Growth as it helps with energy generation with Revitalize.

Start throwing Rejuvenation on everyone when the Green ooze spawns. Just before it reaches its target, use Wild Growth with the Ooze targeted to spread it between damaged units. Be sure to use Regrowth and Rejuvenation on the player targeted by the ooze. In 25 man it could be a bit different : you should prefer rolling Rejuvenation on melee as they will be close to the ooze and follow it till it explodes. Not everyone will stack up in 25.

During transition, hot both oozes' targets and gather on the Green ooze's one. Keep hotting the raid and use Swiftmend on low HP players.

Avoid Goo and flasks in phase 2 and keep doing the same as in phase 1. You can possibly use your Barkskin to keep the Plague a little longer when it's about to fade.

Manage the second transition as the first. If it takes time to get oozes down, remember to hot the tank and be ready to heal it.

In phase 3, we could say Putricide is the opposite of Festergut. Start by healing the tank a lot, then switch progressively on the raid while keeping the tank with full hots (Lifebloom x3, Rejuvenation and Regrowth). Remember to use Barkskin when damages taken start to be heavy. Also, keep avoiding Goo, flasks and poison puddles.