Sealnado, also known as the Twister, is a Boss Monster introduced in the Shipwrecked DLC. It spawns during the Hurricane Season. It cannot be put to sleep with a Pan Flute and is immune to fire. Before its arrival, wind noises will be heard and the characters will quote about an incoming Giant. However, the wind noises can be hard to identify during Strong Winds, making the character quotes the only way to detect Sealnado's approach, therefore Characters that cannot speak are at a disadvantage. Defeating the boss in the Tornado form will drop Turbine Blades and reveal its Seal form.
If the player refuses to kill the Sealnado in its seal form, it will disappear once the player leaves the approximate vicinity of the seal. When it disappears, it will leave behind a Magic Seal. This choice allows obtaining the Magic Seal without having to face Krampus; however, the Meat reward will be unobtainable. As with any other Mob, the naughtiness only applies when the player directly makes the killing blow, therefore the seal can be killed with help of other Mobs (which may eat Meats), fire (which will cause cooked Meats to drop instead), or Poison (which will cause Meats to be stale) to avoid Krampus while still getting the Meat.
It is not recommended to fight the Sealnado near one's base as certain attacks will quickly decimate a player's Walls and Sandbags. When attacked or when the player gets too close to the Sealnado, it will become aggressive. It will attempt to hit the player with a punch attack, when in range it will create a large twister AoE attack around him, suck up the player, cause 250 damage, drains the player's sanity by 33 and remove a couple of items from their inventory then throw them away. It will also absorb nearby items inside the twister and spit them out. If one fights a Sealnado in the Ocean, its twister will instead first make some waves facing Sealnado. Then shoots away Big Waves all around him. When the character gets too close to the Sealnado, they will lose Sanity.
The basic strategy is to hit the Sealnado twice and run back. When the Sealnado performs the AoE attack, the player has about 5 seconds to get away. A safe distance includes the Sealnado off of the screen plus slightly more. The Sealnado AoE attack is done as one of the first couple attacks during encounter. After a couple of normal hits, the Sealnado will make a loud wind sound prior to attacking, chase down the player, do 2-3 more punches, then the Sealnado will do the AoE attack. Ranged weapons like for Harpoon and Boomerang, for example, can be used but they will be absorbed too. For fighting the Sealnado in Tornado form using melee weapons it is recommended to use a Cutlass Supreme and at least a Log Suit. When defeated it will turn into the Seal form, which can be killed easily. When killed in the seal form, it will immediately spawn Krampus.
Below is the number of hits it takes with each weapon to kill a Sealnado when playing with characters with a default damage modifier. The Weather Pain is not included due to the random nature of its projectile.
- The player can stand behind stationary objects when Sealnado starts the tornado and will not be sucked in or take damage.
- Since Sealnado can suck anything near it and Krampus can't move itself onto another island, killing the Seal should not be a big problem if the Sealnado is defeated on an island away from the player's base.
- Luring Sealnado near a few Dragoon Dens during daytime can easily kill it.
- Water Beefalo will mob and kill Sealnado, leaving the defenseless seal form which the player can then kill or spare.
- The Sealnado was introduced in the Wilbur Vs. The Volcano update.
- The Sealnado attacks can remove equipped weapons but not armor.
- The Sealnado, along with Ancient Guardian, Spider Queen and (Palm) Treeguards are the only Boss Monsters in the singleplayer game that are not a mix of two living creatures.
- The name "Sealnado" is a portmanteau of the words "Seal" and "Tornado".
- The Sealnado may also be a reference to the movie Sharknado.
- The Sealnado shares several characteristics with Deerclops, such as spawning during Winter/Hurricane Season, being more dangerous than other bosses towards player structures, and sharing the same melee attack period, attack range, and damage towards a player.
- If attempting to craft something while caught inside the Sealnado, the character will disappear and be unable to move or interact with their inventory or the environment.
- When fighting the Sealnado on sea it will sometimes randomly lose interest in the player, and will not fight back even if the player continuously hits it.
- If the Sealnado begins its AoE attack in the exact moment it is killed, the player will be stuck floating in the air and unable to move. Reloading the game fixes this issue.