Cilan's Crustle

Cilan's Crustle is the second Pokémon Cilan caught in Unova.

Biography
Crustle first appeared as a Dwebble while Ash and the gang were travelling to Nacrene City in BW011: A Home for Dwebble!. Dwebble was making its rock-house, however three other Dwebble attacked it and ran away with its rock. Dwebble attempts to pursue them, but fails. Ash and his friends try to help it, but it runs away, being scared of the trio. Dwebble attacks Pikachu with Slash after he tries to reassure it. However, Pikachu manages to dodge the attack and Dwebble's Slash hits a rock, causing it to hit Pansage on the head. It apologizes to Pansage and runs off after the gang offer their help again.

Later on, Dwebble returns to the group and Cilan invites it for dinner. Due to the rock hitting him earlier, Pansage collapses from a fever, leaving Dwebble feeling extremely guilty. It stands guard over Pansage while it sleeps, but falls asleep beside it. The next day, Dwebble goes to look for its rock. With help from the gang, Dwebble battles and defeats the three Dwebble that stole its rock. After recovering its rock, Dwebble bids goodbye to the gang as they walk away. Suddenly changing its mind, Dwebble runs after them and requests to be a part of Cilan's team. Cilan agrees and captures it.

In BW019: A Connoisseur's Revenge!, Dwebble battled against Burgundy's Dewott. It managed to protect itself from Dewott's attacks by using Protect and its ability Sturdy. Once Dewott grows tired, Dwebble defeats it by using a Shell Smash-boosted X-Scissor.

In BW031: Oshawott's Lost Scalchop!, Dwebble created a huge scalchop out of rock for Ash's Oshawott to use in battle, as its old one was lost after a battle with Stephan's Blitzle.

In BW042: Cilan Versus Trip, Ash Versus Georgia!, it fought against Trip's Gurdurr during the very first round of the Nimbasa Town Club Battle torunament held by the town's Don George. He stood strong against Gurdurr's attacks(including its shell almost broken by Rock Smash) and managed to defeat it with a powerful combination of Rock Slide and Slash, winning Cilan the first round.

In BW050: Battle For The Underground!, It helped Pikachu and Axew escape by burning a hole in the door with it's acid.

In BW064, it was sent to battle Team Rocket who were trying to steal all the rocks from Chargestone Cave. During the battle, it evolved into a Crustle, using its newly-learned Rock Wrecker to defeat Jessie's Woobat.

It appears again in BW065 were it had a Tag battle with Ash's Boldore against Profesor Juniper and Bianca's Accelgor and Excavalier. Boldore was defeated by Accelgor and Escavalier's combined Hyper Beams, but Crustle was able to defeat them alone by using Shell Smash, followed by Rock Wrecker.

In BW069 Crustle defeated both Skyla's Swoobat and Unfezant but was defeated by her Swanna.

Trivia

 * Crustle is the second Pokémon that belongs to a main character to use its ability in the Pokémon: Black & White series. (Ash's Sewaddle-Swadloon's ability was revealed by Burgundy previously.)
 * Crustle is Cilan's first Pokémon to evolve in the anime.
 * When it's out of it's "house", Crustle looks like a lobster.