Tyranitar

Tyranitar is a Rock/Dark Type Pokémon introduced in Pokémon Gold and Silver. It is the evolved form of Pupitar, and the final stage of the Larvitar evolution line.

Origin
Tyranitar seems to draw inspiration from Godzilla, a very popular kaiju in Japanese media.

Reception
Tyranitar has very positive reception from numerous fans of the series for being competitively viable in battle and a very powerful Pokémon all around.

As a Pseudo-Legendary Pokémon, it has very strong stats, including a great physical attack, respectable Sp. Atk, strong bulk and a good HP stat to back it up, allowing it to run many different sets competitively. Although it is slow, it can learn Dragon Dance and Rock Polish to remedy it's low Speed stat, but many prefer Dragon Dance, as Tyranitar can get a boost in both it's physical Attack and Speed.

Tyranitar can also make good use out of Pursuit to play mind games with opponents that use Ghost or Psychic Types.

Tyranitar has a very diverse offensive movepool to effectively utilize it's power. It has an Ability called Sand Stream, which summons a Sandstorm for a few turns. Prior to Generation 6, Sand Stream was permanent in battle until a different weather condition overrides it. From Generation 4 onwards, Sandstorm boosts the Sp. Def stat of Rock Types, allowing Tyranitar some extra special bulk in battle.

In spite of all these battling godsends, Tyranitar's Type combo leaves it rather vulnerable to a plethora of opposing Types, including Water, Grass, Ground, Steel, Bug, Fairy, and especially it's 4x weakness to Fighting.