Tangle Kelp

The Tangle Kelp is a one use, instantly armed aquatic trap, dragging any zombie unlucky enough to cross its path into the watery depths of the Pool.

Usage
Place a Tangle Kelp in any water lane, and it will take down the next single Zombie that touches it. Note that it can only trap one zombie, so if there is final wave and you use a Tangle Kelp it will only trap that zombie.

Suburban Almanac Entry
Tangle Kelp

Tangle Kelp are aquatic plants that pull the first zombie that nears them underwater.

Damage: massive

Usage: single use, on contact

Must be planted in water

"I'm totally invisible," Tangle Kelp thinks to himself. "I'll hide here just below the surface and nobody will see me." His friends tell him they can see him perfectly well, but he'll never change.

Cost: 25

Recharge: slow

Strategy
With such a low cost, Tangle Kelp makes an ideal early defense in pool lanes. Just don't get lulled into failing to build up your pool defenses, because the slow recharge prevents Tangle Kelp from being readily re-used.

They also take down Dolphin Rider Zombies whole instead of being jumped over, so these may be more useful than just placing a Lily Pad in front of it. Furthermore, they are useful in defeating Snorkel Zombies, as they can drown them without having them come up. However, their slow recharge may prevent them from drowning every Dolphin Rider Zombie or Snorkel Zombie, so it's wise to prepare backup plans for them just in case. Squash makes a good backup plan as it is an AoE All-Terrain Tangle Kelp.

Trivia

 * The Tangle Kelp is the only attacking plant that Dolphin Rider Zombies can't jump.
 * Along with the Sea-shroom, the Tangle Kelp is one of two offensive plants that don't require Lily Pads to be in the Pool.
 * The zombie the Tangled Kelp pulls underwater does not die because in the Snorkel Zombie's alimac entry, it says Zombies dont need to breath.
 * Therefore, it is unknown what the Tangle Kelp does to the zombie it pulls down.
 * Maybe they just tangle them until they're squeezed ro death.
 * The Tangle Kelp, the Sea-shroom, the Grave Buster and the Cob Cannon are the only plants that cannot have Pumpkins placed around them, excluding the Pumpkin itself.
 * The Tangle Kelp, the Chomper, the Potato Mine, the Hypno-shroom, and the Squash are the only Instant Kills that are used on contact with the enemy.
 * The Tangle Kelp, the Chomper, and the Squash are the only 1-hits that do not blow up (aww man!)
 * On the Plants vs. Zombies website the Tangle Kelp is seen on land, other than in the water.
 * In the Almanac entry of Tangle Kelp, it says that it thinks Zombies and plants cannot see him. This may be true due to the fact that Zombies never eat him, and Dolphin Riders keep on riding past, when they would normally jump over.
 * Tangle Kelp is one of the twelve plants that appear in the seed selection screen after you get the Grave Buster on the online version. The others are: Ice-shroom, Lily Pad, Potato Mine, Threepeater, Doom-shroom, Jalapeno, Spikeweed, Torchwood, Tall-nut, Cactus and Blover.
 * Tangle Kelp (not including the Imitater Tangle Kelp while transforming), Spikeweed, and Spikerock are the only plants that can't be eaten.
 * Tangle Kelp is basically the aquatic version of Potato Mine except it doesn´t need time to arm and is not AoE. However it costs the same amount of Sun.
 * In Zombotany 2, one Tangle Kelp can kill a Tall-nut Zombie.
 * Tangle_Kelp.jpg this fact, it must do at least 144 peas-of-damage to zombies. That way, if we would have pool Gargantuars, they would almost be drowned almost at the same time, or would have be killed at after few seconds.
 * When tangling a Dolphin Rider Zombie, you can actually see some leftover space where the zombie is suppose to be tangled. This is probably because the Dolphin Rider Zombie is smaller than a normal zombie.
 * The Tangle Kelp's almanac entry says that it's damage is massive, although it's not that massive because it just kills one zombie.