Humiliation is a category of challenges in Call of Duty's multiplayer setting.
Call of Duty 4: Modern Warfare Humiliation Challenges
Airborne
Unlocked at level 42
XP reward: 250
Get a two-kill streak while in mid-air.
Multi-Frag
Unlocked at level 42
XP reward: 250
Kill two enemies with one grenade.
MG Master
Unlocked at level 42
XP reward: 250
Get a five-kill streak while on a mounted machine gun.
Slasher
Unlocked at level 45
XP reward: 250
Get a three-kill streak with the knife.
Multi-C4
Unlocked at level 45
XP reward: 250
Kill two enemies with one C4.
Hot Potato I, II and III
Unlocked at level 45
XP reward: 50, 100, 250
Kill 1, 5 and 15 enemies with a throw-back grenade.
Car Bomb
Unlocked at level 45
XP reward: 50, 100, 250
Kill an enemy by blowing up a car near him.
Backstabber
Unlocked at level 47
XP reward: 255
Kill an enemy by stabbing him in the back with the knife.
Slow But Sure
Unlocked at level 50
XP reward: 250
Kill an enemy while being stunned by a Stun Grenade.
Flashbang Veteran I, II and III
Unlocked at level 47
XP reward: 50, 100, 250
Kill 5, 10, and 25 enemies blinded by a flashbang.
Misery Loves Company I, II and III
Unlocked at level 47
XP reward: 50, 100, 250
Kill one, two, and three enemies with a cooked grenade that has not been thrown.
Ouch I, II and III
Unlocked at level 48
XP reward: 50, 100, 250
Kill 1, 5 and 15 enemies with a non-detonated grenade launcher grenade. (Direct impact.)
Rival
Unlocked at level 48
XP reward: 250
Kill an enemy five times in a match.
Cruelty
Unlocked at level 48
XP reward: 250
Kill an enemy, pick up his weapon, then kill him again with his own weapon.
Think Fast
Unlocked at level 48
XP reward: 250
Kill an enemy with a direct impact from a frag grenade.
Think Fast Stun
Unlocked at level 50
XP reward: 50, 100, 250
Kill an enemy with a direct impact from a Stun grenade.
Think Fast Flash
Unlocked at level 50
XP reward: 500
Kill an enemy with a direct impact from a Flash grenade.
Return to Sender
Unlocked at level 50
XP reward: 250
Kill an enemy by destroying his C4. (Also works on Claymores)
Blindfire
Unlocked at level 50
XP reward: 50, 100, 250
Kill an enemy while you are blinded by a flash grenade.
Call of Duty: World at War Humiliation Challenges
Multi-Frag
Kill 2 or more enemies with a single frag grenade.
XP Reward: 250
Multi-Mine
Kill 2 or more enemies with a single Bouncing Betty/Satchel Charge
XP Reward: 250
Backstabber
Stab an enemy in the back with your knife
XP Reward: 250
Slow but Sure
Kill 1 enemy while you are being poisoned with Tabun Gas
XP Reward: 250
Rival
Kill the same enemy five times in a single match.
XP Reward: 250
Cruelty
Kill an enemy, pick up his weapon, then kill him again with his own weapon.
XP Reward: 250
Special Delivery
Kill 2 enemies by making a Sticky Grenade stick to one and then take out one more when it blows up.
XP Reward: 250
Blindfire
Kill an enemy while you are still dazed by a Signal flare
XP Reward: 250
Return to Sender
Kill an enemy by shooting their own Bouncing Betty/Satchel Charge
XP Reward: 250
Oh No You Don’t
Kill an enemy by shooting a Bouncing Betty right after they plant it.
XP Reward: 250
Misery Loves Company
Kill yourself and 1, 2, 3 enemies with a cooked frag grenade.
XP Reward: 50, 100, 250
Potato Chucker
Finish off an enemy by hitting them directly with a frag grenade.
XP Reward: 250
Think Fast Special
Finish an enemy off by hitting them with either a signal flare or a Tabun Gas Grenade
XP Reward: 250
Car Bomber
Kill 1, 5, 15 enemies by blowing up a car next to them.
XP Reward: 50, 100, 250
Barrel Bomber
Kill 1, 5, 15 enemies by blowing up a barrel next to them.
XP Reward: 50, 100, 250
Hot Potato
Kill 1, 5, 15 enemies with thrown back grenades.
XP Reward: 50, 100, 250
Gib Factory
Kill 1, 5, 15 enemies so that body parts go flying.
XP Reward: 50, 100, 250
Coffin Dodger
Survive the blast from a Bouncing Betty 1, 5, 15 times.
XP Reward: 50, 100, 250
Call of Duty: Modern Warfare 3 Humiliation Challenges
Hot Potato
Kill 5 enemies with thrown back grenades. Reward XP: 3,000
Car Bomb
Kill 5 enemies by destroying cars. Reward XP: 3,000
Backstabber
Stab an enemy in the back with your knife. Reward XP: 3,000
Slow but Sure
Kill 1 enemy while being stunned by a stun grenade.
Misery Loves Company
Kill yourself and 1 enemy by cooking a fragmentation grenade without throwing it. Reward XP: 3,000
Ouch
Kill an enemy with a rifle-mounted grenade launcher without detonation (Direct impact) Reward XP: 3,000
Rival
Kill the same enemy 3 times in a single match.
Cruelty
Kill an enemy, pick up his weapon, then kill him again with his own weapon. Reward XP: 3,000
Think Fast
Finish off an enemy by hitting them with a fragmentation grenade. (Direct impact) Reward XP: 3,000
Think Fast Stun
Finish off an enemy by hitting them with a stun grenade. (Direct impact) Reward XP: 3,000
Think Fast Flash
Finish off an enemy by hitting them with a flash grenade. (Direct impact) Reward XP: 3,000
Return to Sender
Kill 1 enemy by shooting their own explosive. Reward XP: 3,000
Blindfire
Kill an enemy while you are still dazed by a flashbang. Reward XP: 3,000
Hard Landing
Kill an enemy that is in mid-air. Reward XP: 3,000
Extreme Cruelty
Kill every member of the enemy team (4 enemy minimum) without dying. Reward XP: 3,000
Tango Down
Kill every member of the enemy team. (4 enemy minimum) Reward XP: 3,000
Counter-MVP
Kill the #1 player of the enemy team 10 times in a single match. Reward XP: 3,000