The Conehead Groom is one of the bosses in Castle Crashers. Due to his very quick and powerful attacks and his incredible movement speed, he is one of the most challenging bosses in the game, if not the most; as the Necromancer is only considered difficult because of the enemies before him, and as a standalone boss he's very easy, even on Insane Mode.
Background
He founded the Conehead Army. When he died, the Cyclops, upon exiting the restroom, was deeply saddened by his death, and leaves with the Green Princess. It's also assumed that Conehead Groom is the King of Flowery Field, Wedding Crash, Church Store and Parade locations in Overworld Map.
Involvement
He tries to marry the Green Princess after her kidnapping in his Cathedral stronghold. After crashing his party, he will take his would-be bride to the altar, where the battle will start.
Following his demise, he also appears later as an undead warrior for the Cyclops, released from the same coffin witnessed earlier in the game. When the Undead Groom enters, he does 81 damage to any unlucky players who wander near. When the Undead Cyclops is killed, the boss chest lands on him showing a ghost of the groom and cyclops. He makes one final appearance at the ending celebration, as a ghost playing a harp.
Strategy
The fastest way by far of killing him is to use bombs. It will only take around 4 bombs to kill him so it will only take a few seconds. On Insane Mode, you will need 40, but if all four players all carry max bombs they can carry up to 36 bombs.
Another good way to dispose of the Conehead Groom is by using the "What Piano?" technique. The basic idea is to have two or more max agility characters standing at both sides of him (the farther apart the better, as he can throw bombs at you, which can knock one of the max agility players over or force them to dodge, when it could be avoided just by staying spread apart). Each character spams arrows, and the Conehead Groom will seldom touch the floor. The more players there are spamming arrows, the less probable he'll touch the floor. When he hops on the Cannon Piano and plays, he will be invincible, so don't bother attacking him. Instead, you'll need to avoid the target markers on the ground. The easiest way to avoid this is by levitating via 
Levitation, or the "MLG Fly Forever Method". Also keep an eye on the Conehead Groom as he hops back off of the piano. He'll sometimes catch you off guard with a spin attack and bomb spam that easily goes through one or two potions on Insane mode, even with max defense. If he kills your teammate, don't revive them until he goes back to the piano. If the revival is interrupted by the bombs, it's not quite as disastrous as being interrupted by a spin attack (it's generally a good idea to consider it a death-wish to revive teammates as long as there are still enemies alive). Every time the Conehead Groom hops back on the organ, the barrage of cannonballs will continue to get faster as he loses more health. When using the "What Piano?" technique, the Conehead
Cannon Organ
Groom will rarely use the piano in excess of two to five times. Keep moving/levitating to avoid being hit and repeat the process until he's been defeated.
Side note: If, by chance, the groom is downed, he is susceptible to being spammed by stomp attacks, allowing for (relatively) safe damage-dealing. This is easier with multiple players, but still possible with one (so long as you make sure to move properly, so as to keep him under your feet). The more agility you have, the easier it is to align yourself with him in order to keep the spam attack chain going. The Conehead Groom can also be juggled with , so long as you delay your first hit in order to not just immediately knock him over and end the combo with a single hit. This works on other heavyweight enemies as well.
The Conehead Groom can't escape this, because as it is with light enemies, it's an infinite juggle combo, making it the safest possible tactic to fight the groom with. With more than one player, you can twin juggle him with , or both players can go beefy and air-combo him to perform "The Windmill", though this only works on the PlayStation 3 Version as the windmill juggling combo only works because of the messed up physics and smoother movement.
The Conehead Groom can also be easily killed with the blue knight's famous infinite combo lock with ( for switch players). He may block attacks with his shield sometimes, but it is still an effective way of killing him.
Flying Conehead Groom Glitch
The Conehead Groom's Fight Glitch is a glitch caused when throwing the Conehead Groom while in Beefy form, which will cause the groom to fly across the battle area in loops until he reaches an area above a bench or is hit again. This glitch has no practical effect.
Trivia
- Throughout the fight, the Conehead Groom uses dark magic which suggests that he was empowered by the Evil Wizard.
- If the Groom is the Cyclops's son, then he would have to be a hybrid of some sort, as the Groom is human (or half-human/cyclops).
- The Conehead Groom's two eyes can also be seen in the beginning of the level, Wedding Crash, as they pop out of his visor when he is startled by the player's appearance.
The groom's shocked expression
- The Groom can be seen in his "angel-risen" form twice, first he is seen after the boss chest crushes him and the Undead Cyclops, and again in the Barracks at the end of the game; in both he plays an angelic harp.
- While running to the Organ, the Groom will block all incoming attacks with his shield.
- Conehead Groom and Necromancer are the only bosses that do the peace-sign pose when hit by Pink Knights splash magic.
- If you hit the Conehead groom as soon as he starts running up to the organ (when he is one hit from death) he will take the hit and die, but continue running to his organ. He will play it, and as soon as he leaves the organ he dies.
Video Walkthrough
Note: Since he is part of the stage Wedding Crash, that level is included in this video. (Skip to 10:25 for the fight with the Conehead Groom)
