Plesioth

General Notes

• It can be fished out with a Frog in certain areas, when being fished out, the Plesioth will not enter rage mode, as well as move for a few seconds giving hunters plenty of time to deal great damage.
• Using a Sonic Bomb is an easy alternative to fishing out a Plesioth. Just be cautious that it will enter rage mode upon recovering.
• The dorsal fin can be broken by hitting the Plesioth in the belly.
• When near death, Plesioth won't enter rage mode if affected by a Sonic Bomb's sound.
• When near death, Plesioth will put its dorsal fin down.
• If Plesioth is killed in water, it will sink and then come back up and float on the surface. This, of course, means no carves are possible. This is not an issue in Monster Hunter 3 Ultimate. 
• Plesioth's design is based off of an unknown species of shark.
• Plesioth's name bears similarities to that of the Plesiosaurus, an extinct, aquatic, long necked marine reptile of the Mesozoic.

Monster Hunter Freedom 2

• Beware of the Plesioth's Hip Check, which has an unusually large, disjointed hitbox that strikes from standing behind Plesioth.
• Plesioth can limp, but this is very rare.

Monster Hunter 3 Ultimate

• Plesioth returns, where the hunter is able to fight it underwater as well as on land.
• Plesioth will lower its back fin when hungry. After it regains stamina or becomes enraged, it will raise its back fin again. When close to death, it will actually limp instead of lowering its back fin.
  • Plesioth will sleep in area 11 of the Deserted Island in order to recover health, unlike Leviathans, which flee to area 12.
• Additionally, with the introduction of underwater combat, Plesioth can now be killed underwater and still be carved. 
• The fin on Plesioth's head (as well as the head itself being scratched), and on its wings can now be broken in addition to its main dorsal fin.
• Plesioth can recover its stamina by eating Epioth in Area 10.
  • It can also eat from the Epioth corpse in Area 11, although this is less common.
• Interestingly enough, Plesioth is interested in land-based prey as well, as it is seen preying on an Aptonoth in the Plesioth Ecology cinematic.
• The hitboxes on Plesioth's Hip Check are, for the most part, fixed, no longer striking behind it, and they no longer strike as wide an area as before. Its tail spin also has more realistic hitboxes, dropping lower to the ground as Plesioth bends its knees when spinning.
• The Plesioth can be hit with a Fishing Harpoon to make it drop a shiny.

Monster Hunter 4 Ultimate

• A young Plesioth appears as a cameo, swimming off the coast of Cheeko Sands.
  • There is a minigame where the Palicoes can fish out the young Plesioth and earn Plesioth materials, but Plesioth will only appear occasionally.

Monster Hunter Generations

• Plesioth can swim in Area 7 of the Misty Peaks.
• Plesioth will eat from a corpse to recover its stamina.
• When in Rage Mode, Plesioth will swing its head from side to side while breathing its water beam.
• Plesioth now has a stronger version of its Hip Check, in which it slowly readies itself to strike before actually attacking.
• Now, when Plesioth has recently jumped out of water, some of its physical attacks cause Waterblight.
• Its bite now causes the status effect, Sleep.

Monster Hunter Online

• Plesioth is fought differently than in the main series. You control a Wyvern Hunting Boat to fight Plesioth at Great Fortress Lake, using a cannon to attack the monster.

Monster Hunter Stories

• Plesioth can't be found in game, however it's possible to find some of its materials and craft its equipment.