Bonetail

"AROOOOOOOOOOOOO!"

- Bonetail

Bonetail is a large skeletal Dragon in Paper Mario: The Thousand-Year Door, living at the bottom of the Pit of 100 Trials. In the German version of the game, Bonetail is depicted as a female, and in the Italian version, Bonetail's name is derived from "Cassandra", a girl's name. In the Japanese version, all three dragons have "baba" in their name, which means "old woman".

He is the older brother of Gloomtail and Hooktail. As his name implies, he is merely a skeleton of a Dragon, having died of old age after not eating anything for centuries at the bottom of the Pit of 100 Trials. He was once a pet of the Shadow Queen, and was put in the pit to guard and punish anyone of her choice. Any of his actions outside of the Pit of 100 Trials, if any, are unknown.

After Mario and his teammates reach the bottom floor of the Pit of 100 Trials, Bonetail will roar, making it questionable if he can talk, as he has not ever demonstrated that ability. Bonetail's many breaths cause a variety of status ailments in addition to dealing damage. His blue breath can freeze Mario, green breath can confuse him, purple can shrink him and white can put him to sleep. All of his breaths can be avoided with Shell Shield. He can also restore his HP if it's low. Eventually, Mario defeated him and Bonetail coughed up a chest containing the Return Postage Badge.

Bonetail is the strongest enemy in the game, even stronger than the Shadow Queen. He is not necessarily harder than the Shadow Queen though, because the Shadow Queen has two hands, which can allow her to attack more than once per turn. It's also interesting to note that Bonetail has the same default attack and defense stats as Gloomtail. However, the strain of completing the previous 99 levels of the Pit of 100 Trials contributes to the difficulties faced when fighting Bonetail, as items, FP, and HP are more likely to be depleted by the time he is reached than when the player confronts the Shadow Queen. If the player is skilled enough, it is very possible to defeat Bonetail before fighting his youngest sibling, Hooktail. Despite being the strongest boss, Bonetail only offers one Star Point after defeat, just like the Shadow Queen.

Trivia

 * Depending on which partner is accompanying Mario when he enters the 100th floor, the partner will make a short exclamation about the shock of finding such a huge dragon.
 * Bonetail plays the same role in this game as Culex did in Super Mario RPG: Legend of the Seven Stars, The Master (in his final form) did in the original Paper Mario, Shadoo in Super Paper Mario, and Bowser X in Mario & Luigi: Bowser's Inside Story in that they are all completely optional and stronger than the final bosses from their respective games. Wracktail somewhat plays a similar role in Super Paper Mario, as he is a white dragon (like how the first boss is a red dragon) who is much stronger, and completely optional, though Wracktail is not more difficult if Mario and his team avoid all his attacks (and may be easier if the player has Luigi), and is not a skeleton.
 * Even if he is the strongest boss, he only offers one Star Point after defeat, just as the Shadow Queen does.
 * Bonetail's attack and defense stats are exactly the same as Gloomtail's, by default.
 * It is possible to beat Bonetail before even fighting Hooktail. The player must exit Hooktail's Castle before fighting her and go down to the Pit of 100 Trials and survive until the end.