Crystal is the most survivability-focused mutant in the game. Being the only character with 10 HP, Crystal already has a defensive advantage. Additionally, Crystal can safely avoid most projectiles through the use of her active Crystal Shield that is created by her tightening up her butt until it quickly explodes into the big crystal that she hides in. Her ease of use and extra health makes Crystal a great starting character.

Features

Crystal can create a shield around herself which prevents damage. The shield can be sustained for a short duration and Crystal can't move when her shield is activated. The shield will start shaking before automatically deactivating. Crystal is vulnerable to damage during the shield's disappear animation. This shield is fine-tuned to block many attacks when timed correctly, such as a bullet beam from the Nuclear Throne or Big Bandit's barrage. Also COMPLETELY breaks Lil' Hunter.

Special

Crystal can create a shield around herself which prevents damage. The shield can be sustained for a short duration and Crystal can't move when her shield is activated. The shield will start shaking before automatically deactivating. Crystal is vulnerable to damage during the shield's disappear animation. The ability can't be used again until the previous shield fully disappears. Enemies will act as if they have lost sight of Crystal when she is shielding, and closer enemies will get repelled.

Attacks deflected by the shield:

• Common red projectiles such as those fired by Big Dog or Bandits,
• Shotgun pellets such as those fired by Alligators or Mole Sarges,
• I.D.P.D. blue bullets and Inspector's slug projectile,
• Discs from the Disc Gun,
• Cars thrown by Snowbots,
• Maggots shot by Giant Flies

Attacks negated by the shield:

• Green ovoid bullets such as those emitted by Scorpions or Ballguys,
• Rockets such as those fired by Jocks or Golden Snow Tanks,
• Fire, including the blue fire emitted by Lil' Hunter,
• Toxin from toxic barrels and Toxic Ballguys or your own weapon,
• Green bullets and orbs fired by the Palace enemies,

Attacks that bypass the shield:

• Melee strikes such as that employed by the Assassin,
• Lasers fired by Laser Crystals,
• Lightning fired by Lightning Crystals,
• Explosions,
• Contact damage (Though enemies act as if they have lost sight of Crystal when shielding and won't run directly at her. Closer enemies will get repelled).

Co-op: Crystal's reflected bullets do not hurt the other player.

Throne Butt

Crystal's Throne Butt reduces the shielding time and allows Crystal to teleport towards the cursor after her shield disappears. Aiming the cursor over a wall will only activate the shield without teleporting.

Ultra Mutations

	Fortress Adds 6 max HP. Crystal will instantly get healed for 6 HP. Can be stacked with Rhino Skin for a max of 20 HP.
	Juggernaut Enables slowed movement while shielding.

Gameplay

Crystal can be considered the best starting character for a new player due to her survivability. Her health boost alongside her special ability helps withstand heavy fire, plus the shield's reflective properties allow the player to kill enemies without spending ammunition. Releasing the shield and activating it again in the right moments can make you invulnerable for long enough that you can survey the situation before running to safety, which can be really helpful in the third stage. Her teleportation ability with Throne Butt adds to this, as you can escape any danger by shielding and teleporting to a safe location.

Useful mutations:

• Euphoria - grants slightly more time to put up a shield and, in turn, evade projectiles.
• Throne Butt - grants more maneuverability and battlefield control via teleportation. It helps to shield and teleport out of the danger. However, using it effectively requires experience, as it is easy to teleport into the danger, dying to contact damage or bullets.
• Gamma Guts - when combined with Throne Butt, lets you teleport straight into enemies susceptible to contact damage. Doesn't save from contact damage from enemies who survive gamma guts, or from bullets.
• Extra Feet - if you choose to use Juggernaut, this will substantially increase speed you have while moving shielded. (If you choose Fortress, the benefit is reduced.)
• Rhino Skin - added to Crystal's already above-average HP, grants a higher maximum total than any other character. Stacks with Fortress for 20 HP.
• Stress - a higher maximum HP means it is possible to reach a lower minimum percentage of HP remaining, in turn increasing the fire-rate increase cap to one unmatched except by Chicken at 0% HP.
• Second Stomach - Crystal's high max HP gives Second Stomach more room to work effectively, which is further amplified by using Rhino Skin and/or Fortress.
• Rabbit Paw - combines well with Second Stomach, but helps recovering increased health even by itself.
• Bloodlust - Just like Second Stomach it helps heal faster your high max HP. Also acts a substitute for mini medkits if you picked the Crown of Life.

Useful crowns:

• Crown of Protection: Allows you to restore high maximum HP of Crystal faster.
• Crown of Life: Crystal has an easier time surviving with this crown than other characters due to her high HP.

Trivia

• Crystal's loading screen tip mentions "Family". Crystal came from the Crystal Caves and her family is still there, trapped in crystal form. Crystal is the only one that can still control her own body and has any memory of the time before the apocalypse.
• Crystal's other loading screen tip mentions that "Crystal can handle this", which implies that she is confident of her abilities and stays motivated.
• Prior to update #82, Crystal's shield remained active for much longer. It got replaced with a slightly smaller, snappier shield. At the same time, her Throne Butt changed to teleport her after shielding instead of before shielding.
• Shielding near an end portal as Crystal will cause the shield to simply move towards the portal and will linger a bit after the portal takes Crystal to the next level.
• Crystal's appearance and special ability could possibly be a reference to the Deadrock from The Legend of Zelda: A Link to the Past. Similar to Crystal, a Deadrock is able to turn into an impenetrable statue that blocks all damage. The Deadrock statue looks strikingly like Crystal.
• Crystal is one of the original five characters.