Due to his homicidal tendencies, Crown Prince Sado of Korea was executed by being trapped in a box until death. Supposedly it took seven days for him to die. They executed him that way as a weird workaround for some Korean laws at the time.

https://en.wikipedia.org/wiki/Crown_Prince_Sado

"Rumours that Sado had attempted to enter the upper palace to kill King Yeongjo spread around the court [...] By court rules, the body of a royal could not be defiled and, under the then-common practice of communal punishment, Sado's wife and son (the family's only direct male heir) could also face death or banishment if he were executed as a criminal. As a solution, Yeongjo ordered Sado to climb into a wooden rice chest (roughly 4x4x4ft) on a hot July day in 1762. According to Lady Hyegyeong's memoirs, Sado begged for his life before getting into the chest, though he attempted to get out again [...] After two days, King Yeongjo had the chest containing Sado tied with rope, covered with grass, and moved to the upper palace. Sado responded from inside the chest until the night of the seventh day; the chest was opened and he was pronounced dead on the eighth day."