From Bulbapedia, the community-driven Pokémon encyclopedia.
The Fossilized Rain Dance Deck is a type deck found in the Pokémon Trading Card Game Fossil Expansion Player's Guide. The deck is classified as one of the tournament winning decks, containing more rare cards and strategy than other easy-to-build decks.
CONCEPTS: "Rain Dance" is a mono-Water Evolution Deck with a whole lot of firepower. The deck is chock full of heavy hitting monsters that can dish out damage like no other. The natural high-energy attack requirements of this deck's soldiers are balanced nicely by Blastoise's Rain Dance Pokémon Power. In fact, many players believe that Rain Dance is unbalanced, and unfair to use in tournaments. Don't let the frowns on the opposing player's faces deter you however. There can only one Pokémon Master!
TIPS FOR PLAYING: This deck has a very simple goal: Get Blastoise out as soon as possible. Blastoise is critical to the all-important rush of attacks that will overrun the opponent. Rain Dance decks like this one sacrifice quite a bit in the quantity of monster cards department in order to rush into powerful attacks first. If the defending player has the time and opportunity to develop some good opposition on their bench, you may not have the depth to handle their imminent onslaught. With lots of Professor Oak, Computer Search, and Item Finder cards at your disposal, you should be looking at getting Blastoise into play as early as turn number 2. Pokémon Breeder makes this possible and is the preferred method of evolving your first Squirtle in play. There are so many duplicates to rely on in this deck construction, don't be afraid to Oak away a Blastoise or Pokémon Breeder in your hand if you lack that all-necessary Squirtle to get into play. Of course Computer Searching for a solitary missing link is probably the best tactic in that situation, but typically Search should be reserved for retrieving additional Professor Oaks to keep the Water energy cards flowing from your deck.
Rain Dance decks gained some great new cards to revitalize the archetype in the Fossil expansion. The best new additions from Fossil are Lapras and Articuno. They have key features that make them invaluable in this new class of Rain Dance deck. It's almost as if the original Pocket Monster Card Game designers felt sorry for what they did to hamper Rain Dance with the Jungle expansion. Scyther and Mr. Mime are both Jungle cards that together murdered Rain Dance's previously feared and respected role in the tournament environment.
Lapras is a basic Pokémon with relatively small attacks for this deck, but it should never be taken lightly. Both of Lapras' attack moves are vital to defeat Mr. Mime opposition. Mr. Mime's Invisible Wall has historically shut down Rain Dance decks unless they included status inducing or weak attackers (Lickitung was a classic retrofit). Water Gun has the nice feature of growing with additional development, and against a Psychic deck employing that Invisible Wall it can sneak under. Be sure to halt Lapras' supply of Water energy at 2 such that Water Gun is only inflicting 20 damage per round—the maximum that Mr. Mime will allow. And 2 Water energy is perfect for Confuse Ray, which happens to be a better defense against Pokémon Powers like Invisible Wall than Water Gun. Once confused, the Wall will turn "off" and Mr. Mime will be ripe for the fainting.
Articuno is the key attacker in this Fossilized Rain Dance deck. For a basic Pokémon with 70 Hit Points and two nasty attack moves, Articuno is a no-brainer for inclusion into any Water deck. And luckily for us, Rain Dance is just what that "Arti" needs to pump up in no time. Since most Pokémon that a Rain Dance player will have in play at any one time are extremely buff, don't worry too much about failed coin flips with Blizzard. The 50% of the time that your opponent's benched Pokémon are being hit by this damage will more than make up for a few extra damage counters on your own monsters. And, as always, when one hit with a 50-damage blizzard is not enough to take out the defending Pokémon, use Freeze Dry and try to paralyze them. This is especially useful in match ups with other Rain Dance decks.
PITFALLS: Rain Dance's historical pitfalls were plentiful, and the Fossil expansion just adds to the list. Fortunately Rain Dance is fast and brutal enough to bypass many of the Pokémon designed to short circuit it, and the new Water Pokémon from Fossil continue to shift power back to the Rain Dance player. The shift away from Gyarados makes it less susceptible to Scyther, and we already know how to deal with Mr. Mime.
This particular Rain Dance deck suffers badly to Lightning attacks. Be sure to use Lapras and Articuno's status effects (confusion and paralysis) on all yellow opponents. This will slow their approach and keep you in control of the match. Also, two new Pokémon from the Fossil expansion should be feared: Muk and Aerodactyl. If your opponent can get one of these Rain Dance "hosers" into play before Blastoise can work its magic, you may be done for. Use Gust of Wind and your meanest attacker (Articuno) to bring these monsters up front and take them down.