A Freeware arena Shoot 'Em Up that centers around user-made content. The game comes with an editor that lets you make your own enemies, then lets you blow them to bits.It comprises of two modes: Free Play, which pits you against one or more of the available enemies and Try, which gives the player different scenarios. The latter is not as popular, due to the fact that it's harder to make scenarios than enemies.Available Here, with more bosses available here.
The use of the Screen (blur) effector looped just to confuse the player is one example.
Fan Fic: Some of the more prevalent boss makers out there like to put together stories to go with their bosses. Eboshidori is one (his "Mara" series is finished and on YouTube), as is A70M1C (the "][nfector" series).
Getting your boss ][nfected is actually a very great honor for you as a boss creator.
Follow the Leader: Eboshidori pretty much singlehandedly invented the "What If...?" scenarios, the Search-Light wings, custom player weapons and the very, very often used "Globe of light spewing bullets" type of boss. And many, many creations with borrowed ideas followed.
Kinda subverted in the fact that everybody is aware of that. Eboshidori is to Fraxy, is what Simpsons are to animated sitcoms.
Game-Breaking Bug: Several bosses don't work properly in the latest beta versions, despite appearing fine in the editor. These include Eboshidori's Virupaksa II and Sakra-Devanam(This one recently began working again, however). Oneshiningstar's CX-07: Giant Delta 3 has its 3rd delta self-destruct for no apparent reason just before the 4th phase begins. However, if it was not so, you'd be panicking. That thing is spam.
One-Winged Angel: The Fraxy community loves this trope, as many bosses utilize this.
A Famous Example is A70M1C's Osiris, which seems to be a mechanical thing before transforming into an Energy Being for a long battle.
Atomic Vault 99, which turns out to be holding The Avatar, Osiris's first form. However, on Hard Mode, it spectacularly transforms into Osiris for an extremely long battle.
Usually, anyway. It be beaten in under a minute with the correct equipment and levels.
Eboshidori recently created one for the Final Boss of his Fan Fic Fragments of Men, Samsara. After nearly depleting his life bar, he merges with a crucifix, then attemps to fly to the top of the screen. If you don't beat him before then, he, cross and all, transform into his angelic Sunyata form, which rains even more Bullet Hell down on you than before. Admittedly, fighting him like that is a lot better than just beating his temporary Clipped Wing Angel form, but still...
Actually, you need to destroy an item box when he stops teleporting and starts to re-energize. Otherwise, he just crucifies himself.
A70M1C's ][nfected seem to be based on the Flood from Halo and the Beast from Homeworld Cataclysm.
Not just to games: Eboshidori based Sunyata's design off of the 15th Angel.
It shouldn't be surprising that Touhou gets a little homage of its own on several occasions.
Special mention must go to Pure Question's Great Shining Seal. It has named danmaku attacks called "Lost Arts". Guess what is the only other game series anyone can think of that has named danmaku patterns?
Someone made a Yukkuri boss, which actually uses different spellcards (Touhou ones, obviously. No names.), and it changes its face per spellcard, too. It has; Lingering Cold, One-Legged Return Hit, Icicle Fall (No, it didn't double the memes by making it the easy variant - it's the one with the aimed shots), Terrifying Hypnotism minus the lasers (VERY appropriate considering what the boss is doing.), Kandata's Rope (Fortuantely, it doesn't last anywhere near as logn or get anywhere NEAR as difficult as the original), Flying Phoenix, Ancestors Standing Beside Your Bed, and (not shown in the video) Forbidden Fruit. Yes, that's no less than 3 extra boss spellcards, at least one from Aya's games, and some of the somewhat memetic characters' spellcards (hell, one of them is simply the non-memetic version!)
Soon after, another boss maker named hexidextrous decided to make more Touhou-esque bosses as a tribute to the above boss. He has currently made bosses based off of Kisume, the previously mentioned Yukkuri, Medicine Melancholy, Ran, Yuyuko, and Patchouli Knowledge.
Sinister Geometry: Oomagatuhi's DANMAKU-DAMASII-Mk5 as well as Eboshidori's True Acala and the second form of Broken Dream.
Trick Boss: Possible, but rare. Usually involves the rest of the boss suddenly becoming visible!
A more notable offender is the Clock Trap, which starts out as a harmless, unprotected core until you find out that was a holding mechanisim for a robotic laser blender that you'd be crazy to take on. Luckily, it's also defeated by managing to escape it's gravitational pull and the surrounding laser emitters on top of being dedicated enough to destroy it's core.
Turns Red: Almost all the time. Number of times vary considerably, but generally, the more times, the more painful.
Up to Eleven: "Death Label" Bosses, which are harder versions of other bosses.
Urban Legend of Zelda: Supposedly a Try editor is in the works, but no one knows when Mon (the game's creator) will have time to work on it.
Or even whether he will even start on it.
Wave Motion Gun - The Laser. Bonus points for being available in three different sizes.
What Do You Mean, It's Not Symbolic?: Several bosses are re-imaginings of deities from several religions (Eboshidori's guardian series is built around this, with every Buddhist Deity except for the Buddha himself showing up and the protagonist being the Buddhist devil ), one sticks the player on a crucifix, and one crucifies himself to achieve his final form.
Body Horror: A70M1C's ][nfected start out normal, then turn into a freaking horror shortly after taking enough damage.
Corrupt Church: Omoresu's Angelo Storyline has the Nyghts Clique, who worship Angelus.
Boxorak's Soul Harvest had the Skelati, beings that harvest souls in an attempt to both appease their god and free him from a dimensional rift.
Designated Hero: Mara. No matter who created him or why, no matter the intentions, Mara has the simple mission of killing Sakra-devanam and her spawn for attempted (and possibly accomplished) genocide of humanity. If he needs to devastate an alien fleet for making the simple mistake of experementing with Sakra-devanam's oddly shapedressurection leeches, so be it.
Serial Escalation: Eboshidori created a boss called Matrix Hibachi, which was pretty hard. Shortly after, he gave us the "Death Label" version, which had bullet patterns similar to the original, only harder. To clarify, the original was already Bullet Hell.
Zarro Tsu, in what seems to be a complete "Screw You" to the player, released the "Death Label" version of his A.N.G.E.L. Boss. This is regarded as a completely evil move because....well, see Death Is a Slap on the Wrist.