Vaporeon

Type Tier
Water BL
Statistics
Stat
HP
130
463
Atk
65
228
Def
60
218
SpA
110
318
SpD
95
288
Spe
65
228
Name Item

Hazing Vaporeon

Leftovers
Moveset
~ Reflect
~ Haze
~ Surf
~ Rest

Hazing Vaporeon. Good for Cursers, especially when the Curser has Earthquake. Reflect up, and you'll get a good turn to Haze with the high HP. Surf whatever with that meaty Special Attack, and Rest when necessary.

Name Item

Growtheon

Leftovers
Moveset
~ Surf
~ Growth
~ Rest
~ Ice Beam / Baton Pass / Sleep Talk

The Growth version. Ice Beam if you're paranoid about Zapdos and Exeggutor, Baton Pass can give the Growths to, say, Zapdos or Houndoom, and Sleep Talk could make it like the special version of Ursaring.

Name Item

Cursing Vaporeon

Leftovers
Moveset
~ Curse
~ Body Slam
~ Baton Pass
~ Surf / Ice Beam

Curse patches up Vaporeon's sub-par Defense while boosting its Attack, meaning you can hit Blissey or Tentacruel with a Cursed Body Slam. If something comes that could hurt you, Baton Pass the Curses to something else. Surf has STAB, and Ice Beam will hit Flyers with Whirlwind and Grass-types with Leech Seed.

Other Options

Substitute and Acid Armor could be options for Baton Passing, Toxic (though not a great move) will poison the Water types that Vaporeon can't hurt, and Charm can mess up physical attackers (Snorlax) when they switch in. Vaporeon can use Roar nicely thanks to its low Speed. This also guarantees that its Roar will go after the opponent's (slower Pokemon with Roar / Whirlwind, such as Steelix, are hit hard by Surf), thus letting it succeed. This can be helpful vs. Suicune on a Baton Pass set.

Opinion

Underrated Water-type. The only really bad stat it has is Defense, and that's why most people don't use it. However, it can patch that up in various ways. Great special stats and HP make it a good tank, and that 318 Special Attack will hit most Electrics hard when they switch in. Also one of the few things in GSC that can pull off Baton Pass since the only pseudo-hazer that can Roar it away without taking much damage is Suicune.

Counters

The generic Water-type counters suffice, including Electric Pokemon such as Zapdos and Raikou, Grass-types like Exeggutor and Celebi, and fellow Water-types that can bypass its Water and Ice resistance. Tentacruel Swords Dances up with impunity and smacks down Vaporeon, Starmie hits it with Thunderbolt, and Slowbro's STAB Psychic hurts it. Blissey has trouble with the Growth and Curse sets, but stalls the Haze one. Snorlax wins Curse and Growth wars against Vaporeon.