Tusk, who is a walrus, is a character who appears in the MMO (Massively Multiplayer Online) game Club Penguin. Tusk is the primary boss of Card Jitsu Snow, a mini-game where penguins can become ninjas and fight with cards. Tusk has a hatred for Sensei (a character who trains players to become ninjas) and all ninjas, and he is trying to destroy Sensei and his Dojo. Tusk can attack by raining down icicles at random, as well as creating a giant wall of ice, pushing players to the opposite end of the battlefield. He is the overall tertiary antagonist of the game.
When Tusk was a child, he and Sensei were great friends. They always played together and had snowball fights. Although, one day, Tusk decided to build something out of snow. He made a small igloo out of a few clumps of snow. When he turned around to show Sensei, he saw that Sensei had built a huge snow dojo with amazing detail. Tusk was slightly jealous. Later, they trained together in the art of Card Jitsu. They always wanted to fight side by side in an amazing battle, but Tusk soon came to realize he wasn't as good at Card Jitsu as Sensei. One fateful day, Sensei and Tusk were sparring on a snowy cliff. Tusk threw a snowball, but Sensei managed to push him into a snowy wall. Then, Tusk threw a large snowball at Sensei, who sent it back at Tusk. It hit Tusk, and sent him flying back into the wall. The shaking caused an avalanche, and Tusk was trapped in a cave. Sensei tried to search for him, but only found a piece of his broken left tusk. Sensei left very sadly, bringing his tusk with him, and vowing to teach penguins to use Card Jitsu wisely. But Tusk, on the other hand, thought Sensei had left him. He was very angry, and vowed for revenge. He built a lair out of the snow cave, as well as some armor and a torn cape. He created three snow minions: Sly, an average sized snowman that throws snowballs, Scrap, a thin snowman that hits snowballs with his racquet, and Tank, a large snowman that fights with his fists and has a sled shield. They all regenerate after being destroyed. Tusk sent them to destroy the dojo and the ninjas, but the ninjas managed to prevent their plans. Finally, Sensei and the ninjas confront Tusk in his cave. After a long battle, Sensei and the ninjas are victorious. Tusk laughs evilly, saying that their Sensei had taught them well, but he has more power than all of them. Turning into a shadowy spirit, he disappears, his face showing for a few seconds.
- Sensei's walking stick is Tusk's broken tusk.
- Tusk's favorite food is Swordfish Steak.