For everyone who went through the hell of raising up that Magikarp, just proves how good Gyarados is, both mechanically and aesthetically.
Typing: Water-Flying is a decent start. 5 Resistances plus 1 immunity is never too bad. But then the weaknesses come along and are among the worst in the game. Quad weak to Electric does nothing any favors, and a weakness to Stealth Rock is your door prize for packing a Flying subtype. The Resists, especially to Fighting, Ground and Water are great, but the price to pay is high.
Offensively, Water Flying is a great STAB combo. Flying compliments Water well, cutting down Grass types that are resistant to it and hitting everything else for neutral. Water does likewise for flying, washing away the Rocks that resist it and hitting Steels for neutral.
For some reason Mega-Gyarados becomes a Water-Dark type. For what reason? Beats me. At a first glance, Water-Dark seems beneficial: 6 resistances and 1 immunity are great, and losing the weakness to Stealth Rock, plus a chance to actually survive Electric attacks is a great deal for Mega-dos. Then comes the fact that Mega-dos now has 5 weaknesses instead of 2 and the deal starts to look bad especially with a weakness to Fighting and Bug, two types it used to resist.
Again though, Water-Dark is a great stab combo, though the two types don’t complement each other as well as Water-Flying. No monotype pokemon can resist the STAB combo, and few dual types as well.
Stats: Gyarados has few weaknesses and many strengths. Base 125 Attack instantly screams “sweeper!” and can dent most things fairly well. Gyarados sits at the bulky end of the Sweeper spectrum with Base 95 HP and Base 100 SDEF making it particularly spongy. 79 DEF is just below average and 81 SPD is a tad slow for a non- Trick Room pokemon, but Gyarados has apps for those two stats. Surprisingly, for a pokemon that is commonly depicted spewing beams of cataclysmic proportions, Gyarados’s SATK sucks. Don’t use it.
Mega-Dos takes the title bulky sweeper and cranks it up to 11. 109 DEF and 130 SDEF in conjunction with that high HP is incredibly durable. Add to the equation as heart stopping 155 ATK and Mega-Dos will be haunting your dreams, if not your team’s grave.
Moveset: As mentioned before, Gyarados has a fairly large (but unusable) special moveset. Its physical movepool isn’t as fantastic, but allows Gyarados to get the job done. In addition to its numerous water STABs (Waterfall, Aqua Tail), its physical movepool consists of Bite, Return, Ice Fang, Earthquake, Stone Edge, Payback, Bounce, Iron Head and Outrage is the full extent of the leviathan’s movepool. In addition, Gyarados possesses the coveted Dragon Dance, the first of its Apps that patches its paltry speed and boosts its attack to nuke-tacular levels. Gyarados has little to speak of for a support movepool outside of the standard WTPS (Weather, Toxic, Protect, Substitute), with Taunt, Roar, and Dragon Tail being the standout options.
Abilities: Gyarados is another pokemon that walks away with multiple great abilities. Intimidate, is Gyarados’ second App, patching up its physical defense. Moxie is great in conjunction with Dragon Dance, making Gyarados impossible to stop after a few KOs. Mega-Dos gets the ridiculous Mold Breaker for its ability, which it will use to primarily doom Levitators and anything with Water Absorb and Storm Drain.
The Verdict: “We’re all going to DIEEEEEE!” Gyarados, and its Mega evolution have many strengths and few weaknesses. Be prepared for these leviathans.