COMBO BREAKER
The term C-C-C-C-COMBO BREAKER is from the Arcade and SNES game Killer Instinct. It was taken and is used on 4chan as a mild form of thread hijack. It is used to interrupt a thread with pictures relevant but inappropriate to the nature of the thread, to make fun of obsessive fans, or troll a successful theme thread.
Example: adding suggestive yaoi art to threads of cute girls, such as many Haruhi threads fall victim to.