Every character has over a dozen head customizations you can track down eventually. The missions listed here always reward a head, but the enemies hinted at here do not; they have a chance to drop special heads, just like they have a chance to drop unique and legendary equipment. But a chance is not a guarantee.
Unlocking heads
Defeat any Badass enemy.
Complete mission “Symbiosis.”
Complete mission “In Memoriam.”
Complete mission “Statuesque.”
Complete “…To Pay the Bills” Challenge.
Defeat hidden enemy in Caustic Caverns…
Defeat boss of mission “Best Mother’s Day Ever.”
Defeat boss of mission “Where Angels Fear to Tread.”
Defeat first target of “The Talon of God.”
Defeat second target of “The Talon of God.”
Defeat target of “You. Will. Die. (Seriously.).”
Complete the “Captain Scarlett and Her Pirate’s Booty” DLC campaign.
Complete the “Mr. Torgue’s Campaign of Carnage” DLC campaign.
Complete the “Sir Hammerlock’s Big Game Hunt” DLC campaign.
Complete the “Tiny Tina’s Assault on Dragon Keep” DLC campaign.
Axton the Commando
Maya the Siren
Salvador the Gunzerker
Zero the Assassin
Gaige the Mechromancer
Krieg the Psycho
Getting Skins
Extra vehicle customization skins are found on enemies and in loot piles. Extra player skins are found several ways:
33 are earned by completing various Challenges.
8 are available as the Item of the Day in vending machines.
2 are rare prizes from slot machines.
14 drop from enemies and bosses.
8 are mission rewards.
DLC 69 Fan Beat and Sandskiff skins. Sandskiff skins drop off of pirate enemies. Fan Beat skins can drop off of any enemy.
Missions with Skin Rewards:
“This Town Ain’t Big Enough”
“The Overlooked: Medicine Man”
“To Grandmother’s House We Go”
“Cordially Invited: Party Prep”
Axton the Commando
Salvador the Gunzerker
Maya the Siren
Zero the Assassin
Gaige the Mechromancer
Krieg the Psycho