Bonetail is the oldest sibling of the Hooktail Dragon family and was featured in Paper Mario: The Thousand Year Door. He is so old that his entire body has degenerated entirely to nothing but bones. He also appears to have lost his sanity and intelligence to time, as his only vocalizations are shouting "Aroooo!" semi-randomly while fighting Mario.
Bonetail is by far the strongest and most dangerous of the three dragons, heavily outclassing his younger siblings in HP, Attack Power, and variety of attacks. His attacks include a variable breath attack that can poison, confuse, paralyze, or just plain inflict a huge amount of damage to Mario. He also has the hallmark attacks of the dragon family of stomping and biting.
Bonetail may well be the hardest boss in Paper Mario: The Thousand Year. Because his attacks are extremely strong and he has a base health of 200 HP and often, due to his healing abilities, an effective health approaching 260 (assuming 3x usage of his instant 20HP recovery ability) -- Bonetail can easily end a player who has barely survived the Pit.
It may be safely concluded that the creators of Paper Mario: The Thousand Year Door succeeded in creating an opponent more challenging then the final story boss with Bonetail. Bonetail's difficulty is amplified significantly due to his location at the bottom of the Pit of 100 Trials. As such, Mario well almost certainly be worn out and badly beaten by the time he even reaches Bonetail. The dragon would be a challeging enough opponent if it could be challenged on it's own with no prerequisites, but given that the player will almost certainly go into the battle with few to no items, and several either depleted or drained stats such as Star Power and FP, the fight quickly becomes a struggle for life instead of a challenging fight. If defeated, Bonetail coughs up the extremely rare and useful Return Postage Badge, which can only be obtained this way -- effectively the grand prize of the pit of 100 trials.
Note: It is possible (if hugely difficult) to defeat Bonetail before Hooktail if you have enough badges at the time and at least have both Goombella and Koops as partners. Powering up at least one of them is recomended. He is one of the Strongest Paper Mario Series Enemies!
Battle Tips Edit
This battle can be considered hard for some people, however with a few key elements Bonetail isn't very difficult. If players choose not to battle him in a Pre-Hooktail run, these are ideas you could use. Having the Feeling Fine badges for you and your partners is beneficial to this battle, as only two of his breath attacks are dangerous leaving the other three useless. Having anything that pierces defense is a must have as it'll make getting past Bonetail a lot easier. Using attack buffs such as Power Lift, Charge, or any Power Plus Badges are recommended. Soft Stomp can also be useful here. In terms of party members Madame Flurrie is you go to option as she can completely tank and stall the entire battle for you. Flurrie is a must need for this battle with her Lip Lock ability. As his attack power is only 8, meaning she can already restore 90% of her health back. Influencing Flurrie with attack buffs is also highly recommended. Learning how to Superguard or Guard the other two dragons can also help with this fight too. Using Fire Drive, Power Bounce, Spring Jump, Soft Stomp (two of them) Piercing Blow are all highly effective for this fight. The key is to taking out Bonetail lies in beating him down with powerful moves and surviving all he throws at you. With Flurrie, this makes it all very easy. Player's must also be very packed with healing items and must at least have a very big amount of them depending on their health stat.
Bonetail's defeat will come with recognizing his attack patterns. His varied breath attacks can cause every negative status in the game on top of causing massive amounts of damage, and he will take advantage of an instant-heal for twenty heart points three times over the course of the battle. Alongside Flurrie, make use of Vivian's veil move if you see him charge. Players that cannot cause large amounts of damage and take as much as they give will not survive this fight. If it comes to gradual damage versus mass damage, choose mass damage, as trying to take him down bit by bit or conserving points or items will see the player beaten down before any serious chance of killing the dragon comes within range.