Sunken Scuffle

Sunken Scuffle is the second main campaign world in Plants vs. Zombies: What in the World? Again. Trent and a mysterious new friend venture under the strangly toxic seas.

Opening Cutscene
Trent is seen on the beach, sitting and staring at the defeated Pea Mech. A sillhouette appears in the distance, getting bigger as it approaches. It becomes a redheared girl with blue glasses, introducing herself as Crazy Danielle. Trent and she talked about the current situation. Danielle suggests making a submarine with the ruins of the mech, but it would take some time. Trent is okay with this. Three days later with oddly no Zombie invasions, the Peamarine has been built. Our heroes venture into the water to stop the Zombie leader. However, the deeper the get, the more purple the water seems, until a Brownciat Zombie appears, protected in a bubble. Trent and Davette must adapt to the change of underwater carbon dioxide to continue.

Gimmicks
In order to plant non-underwater Plants here, you must use a Portabubble. You get 5 of these at the start of each level. Some Plants can make bubbles. Very few Sun falls from the sky, at a maximum of 300 Sun. In later levels, Sun stops falling from the sky as a whole, making Sunflowers, Photoplankton, Sun, and Portaplankton essential. This World isn't a 5/5 Difficulty because if you can manage to pop a concealed Zombie's Portabubble, they will instantly be defeated. This also applies for Plants. Zombie Portabubbles can take 15 damage before popping, and Plant Portabubbles can take 4 bites before popping. In later levels, poison can block Plants from being planted in some sections. It does not harm Zombies. Thankfully, the maximum it can spread to without Zombie interaction is the farthest 3 lanes to the right. As such, it is important to stop Scuba Soldier Zombies early, for both their Smoke Bombs and ZPGs.

Levels
Level 1- A normal level with Shameplant as the reward. Bubble Browncoat appears here as this World's variant of the Browncoat.

Level 2- A level that introduces the Bubble Imp, this World's variant of the Imp.

Level 3- A level that introduces the Bubble Conehead Zombie, this World's variant of the Conehead.

Level 4- A normal level.

Level 5- A level that with Eelgrass as the reward. This level introduces the Bubble Buckethead Zombie, this World's variant of the Buckethead Zombie.

Level 6- A level that introduces the Scuba Soldier Zombie. This Zombie is very problematic as when it steps on the 5th lane, the throws a Smoke Bomb two tiles in front of it, spawning a 3×3 area of poison. After this, they shoot a ZPG that destroys a Plant it hits, even its Portabubble if they have one. Plants protected by Portabubbles are not affected by the poison, nor are the Portabubbles. We suggest you use Eelgrass as soon as the Scuba Soldier Zombies appear. They are cheap in terms of Sun and fast. Even though they have low defense, defeating Scuba Soldier Zombies before danger comes is worth them.

Level 7- A normal level.

Level 8- A normal level.

Level 9- A normal level.

Level 10- A level that introduces True Morels and the Angler Zombie. Angler Zombies swim onto the field and shine their almost hypnotizing light, making Plant consider switching sides, stunning them. True Morels are essential for this World from now on, as you only need two of them to protect your entire lawn.

Level 11- A normal level.

Level 12- Sun stops falling from the sky from now on for the rest of this World. You must use Sunflowers now to get Sun.

Level 13- A level that introduces Photoplankton as its reward.

Level 14- A normal level.

Level 15- A level that boasts Boasting Kelp as its reward.

Level 16- A normal level.

Level 17- A Save our Seeds level with 5 Wall-Nuts at the very first lane, protected by Portabubbles. The only Zombies that appear here are Scuba Soldier Zombies.

Level 18- A normal level.

Level 19- A normal level.

Level 20- A normal level.

Level 21- A normal level.

Level 22- This level introduces the Acid PeaBot 7000 as a boss battle with Acidic Peashooter as its reward.

Acidic PeaBot 7000
In phase one, the Acidic Peashooter will shoot 2 Smoke Bombs onto the field and slam into the ground in front of it, stunning all Plants for 2 seconds. In phase two, it will fire 3 Smoke Bombs into the field instead of two. In phase three, its final phase, it will now fire a series of mechanical poison peas, destroying eight plants and stunning the Plants around it for the same time as its slam attack.

Trivia

 * Boasting Kelp was supposed to come before Photoplankton, but their spots were swapped because Photoplankton dosen't have use outside of this World.