Cradily, the Barnacle Pokémon. Cradily is believed to be able to extend its tree branch-like neck and catch prey with its tentacles.
– May’s Pokedex
Cradily is one of the fossil Pokemon in Gen III, the counterpart to Armaldo. Its typing of Rock/Grass is unique to its family. Even though Grass and Rock have lots of weaknesses on their own, when combined, a lot of the weaknesses (like Flying, Water, Ground, and Fire) cancel out, leaving it with only 4 weaknesses.
Cradily is based on the sea lily, which is not actually a plant. Even though it lives in water, it’s also not a Water type.
Stat-wise, it has decent defenses, equal Attack and Sp Attack (so it can go either way, or be a mixed attacker), but very low Speed. It also has a pretty wide movepool, so it can either be a defensive support Pokemon, or an attacker (by using Curse, or Swords Dance).
In Gen V, Cradily gets the ability Storm Drain, which grants it immunity to Water attacks, and raises its Sp Attack by one stage if it’s hit by a Water attack. Even though Cradily is not weak to water, Storm Drain also draws single-target Water attacks to it, so it can protect a teammate that’s weak to Water in double battles.
Cradily would also work well on a Sandstorm team (being Rock type, it would get a Sp Defense boost), or a Sunny Day team (since it’s not weak to Fire, and can use Solar Beam).