SNK Boss Syndrome

SNK Boss Syndrome is an unofficial term to describe the infamously high difficulty of SNK fighting game bosses.

Traits
The syndrome manifests by an overall weakness that is made up for by unfair advantages. There are several recognizable traits that can be linked to a small number of core symptoms typically stemming from poor programming.

Arbitrary advantages over playable characters in the game

 * attacks with unreasonable damage, priority/hitboxes, speed, range or recovery
 * greater defense than average
 * immunity to chip damage
 * unavoidable moves that hit the player regardless of their position, and can only be blocked

Disregard for established gameplay rules

 * no dizzy state when featured in the game
 * infinite or costless super special moves
 * unblockable moves

Absence of reaction time, command input and "human error"

 * ability to read the inputs of a human player and/or appropriately reacting to the player's inputs at the same time as (or even before) the player's own character does
 * inhuman consistency in achieving maneuvers that require precise timing or difficult commands
 * never falling for a command counter unless initiated during the start up of the boss's attack
 * ability to follow up every hit with a combo on reaction regardless of the frame window of the first hit
 * ability to execute special and super special moves without inputting a command
 * ability to do so on reaction
 * ability to counter a fast attack with a faster super move on reaction

This syndrome is often looked down upon as a lazy way of adding difficulty, by putting unfair disadvantages in the way of the player instead of taking the time to design a genuinely challenging AI. SNK bosses typically suffer from various programming flaws as well, leading to exploits and patterns that are most often the easiest way to defeat a boss.

Although named after SNK, the syndrome can be found in many other fighting games, and is not exclusive to bosses; higher difficulty settings are likely to have the AI engage in some degree of this behavior.