Water Dumple

Water Dumples are enemies in all of the main Pikmin games. They are members of the grub-dog family, and act like Dwarf Bulborbs. They are most commonly found in the water, but can survive on land as well. They resemble blue catfish or shellfish, with relatively large mouths, whisker-like features, and tentacles at the rear of their abdomen. Their exact behavior varies with each game, but they can always be defeated easily if the player is cautious and swarms them. Just like other small enemies, Purple Pikmin in will work particularly well if this creature is found on land. A Water Dumple can be defeated easily by leaders as it has few hit points.

Pikmin
In Pikmin, Water Dumples are found in or near bodies of water and always in groups. They have one simple bite attack that can grab only a few Pikmin at a time, and if attacked, they may shake any Pikmin off of their bodies. Though similar in stature to Dwarf Bulborbs, Water Dumples cannot be defeated by one Pikmin thrown directly onto their back, but can be defeated rather quickly, regardless. If a Water Dumple spots a Pikmin or leader, it will give chase and continue for a considerable distance. The light color of the water in The Distant Spring can make Water Dumples difficult to spot.

Pikmin 2
Water Dumples are very much unchanged in Pikmin 2. They, alongside Dweevils, are somewhere inbetween a small and medium sized enemy, in a sense that while a direct hit from a Purple Pikmin doesn't kill them, it does reduce them to half of their health. They are found more frequently on land due to the many caves they appear in that contain little or no water. They move at a slightly slower pace, and their movement animation has been drastically slowed.

Pikmin 3
Water Dumples are similar to their previous appearances in Pikmin 2, but they have gone through a few notable changes. They are found alone or much more spread out in several areas, but still found in water in almost all cases. Since they are frequently single targets, they are also slightly trickier to fight. Most notably, Water Dumples can now counter Pikmin very easily if attacked from the front; with its simple bite, one creature can shake a huge army off its face before taking much damage at all, leaving the attackers vulnerable. The water they live in is much deeper than the previous two games, giving them a sort of camouflage in the water.

Pikmin
Swarming a Water Dumple with a large army of Pikmin is usually very effective. If these enemies are in large groups, however, and you have few Pikmin, it is likely that some Pikmin will be eaten, as the Dumples attack with quick lunges. In such a case, separate the creatures by luring them away from the group one after another. If you lure a Water Dumple too far out, it will lose interest and begin to return to the group or its original location. When this happens, swarm them from behind to ensure a quick and safe victory.

Pikmin 2
The basic strategy for defeating Water Dumples is unchanged; swarm with a large group of Pikmin. However, a few new strategies are brought to the table. If you have Purple Pikmin at your disposal, use them to stun the creature from a distance, and then continue pelting it for a quick defeat. This way is safest, as the creature should not be able to regain its sense fast enough to fight back against the Pikmin. Also, now with stronger punches, it is possible to take out Water Dumples effectively with a leader. This is slower than using Pikmin, but is an effective way to ensure the safety of Blue Pikmin when encountering submerged Water Dumples. Just circle the creature, punching it and backing off when it shakes or bites.

Pikmin 3
One new precaution must be taken with Water Dumples: don't send your squad in from the front. Doing so will result in the Dumple shaking off all Pikmin, no matter how many, and following up with bites. It is best to approach it from the rear and charge from there, or just throw Pikmin onto its back and whistle them back off if/when it attempts to shake them off.

Pikmin 4
Just like the previous 3 games, swarming is the best way to defeat these creatures. Similar to Pikmin 3, they can shake Pikmin off of a forward charge and will retaliate with a quick bite. The best method is to swarm from its rear or to just repeatedly throw Pikmin onto its back until it dies. Additionally, if you want to minimize potential Pikmin deaths you can use Oatchi to attack (and if his Rush skill is high enough, it can one-shot the Water Dumple.

Trivia

 * It is stated in Louie's notes on the Bumbling Snitchbug that Water Dumples lay eggs.
 * Their "whiskers" are only present in Pikmin, having been removed in Pikmin 2 and Pikmin 3 for unknown reasons.
 * In Olimar's notes for the Wogpole, it is said that Water Dumples feed on the creature's eggs.
 * The Water Dumple's design is likely made up of 2 separate species, the and the.
 * In Pikmin 4, during night expeditions, if a Water Dumple is present and turns hostile, it will gain glowing red "eyes" on the side of its body next to where its mouth ends. This suggests that their eyes were there before they deprecated.