Gyarados

Gyarados is an extremely potent threat both offensively and defensively in STABmons. Its typing allows it to resist common offensive moves such as Earthquake, Iron Head, Origin Pulse, and Close Combat and gives it access to Roost, which greatly helps its walling and sweeping capabilities and allows it to check common attackers such as Mega Scizor and Heatran. Access to Intimidate further increases its ability to check physically offensive threats and provides it with more opportunities to set up.

Access to Dragon Dance also allows Gyarados to be an extremely powerful offensive threat. Its Dark typing gained upon Mega Evolving gives Gyarados access to STAB on Crunch, which allows it to beat the likes of Slowbro easily. Gyarados also gains Mold Breaker when Mega-Evolved, which allows it to set up against Unaware users such as Quagsire and Clefable and hit Levitate users such as Rotom-W with Earthquake. Additionally, its Water / Flying typing gives it access to powerful STAB moves such as Crabhammer and Dragon Ascent. Its naturally high bulk and access to Roost make it difficult to revenge kill.

However, Gyarados still has several exploitable weaknesses. Most notable is its 4x weakness to Electric, which is a common attacking type in STABmons. Gyarados's Mega Evolution also gives it a weakness to U-turn and Close Combat. Additionally, its coverage options are not strong enough to get past walls such as Ferrothorn and Skarmory. A weakness to Stealth Rock and common Rock-type coverage in Diamond Storm also reduces its longevity and forces it to Roost often to keep its HP up. It can also be checked by priority status users such as Thundurus and Sableye if it does not have a Substitute set up.