The board game Jumanji is a supernatural game with a mind of its own (some surviving players even claim that it is cursed) that doesn't really rest until those who start playing it, gain the will to finish. There are many copies of this game all over the real world, but none have the same magical power as the original to send players into its African jungle-like alternate reality or to send the dangers of said reality into the real world. Jumanji gets antsy when it is left unfinished, and while on occasion it sends its outerspace-themed "sibling", Zathura, to keep its abandoners busy and unable to escape unless the space adventure is finished, Jumanji has the tendency to mess with said players itself with its savage-jungle nature. The only thing that that the Jumanji game hates more then being left unplayed (to the point its drum-like "heart" is heard) is cheaters, so whenever someone plays dishonestly by changing the dice, or tampering with one of its inter-reality puzzles and minigames, that very player has to face magical punishment by getting turned into an animal, more-often-then-not a monkey.
Many previous players tried to get rid of it, usually by burying it, burning it, and/or floating it down a river to sink at sea, but due to its magic, there are rumors that original version of the game still survives somewhere, waiting to be played yet again so it could use its dangerous, yet character-building power on those who need/want to "leave their world behind" the most.
The name "Jumanji" is the zulu word for "many effects" which explains its unpredictable nature and magic.
NOTE FROM A NATIVE ZULU SPEAKER: The word Jumanji is not from the Zulu language.