The Cardboard Box is one of Solid Snake's taunts in Super Smash Bros. Brawl and Super Smash Bros. Ultimate. It is notable for being the only taunt Snake can use other than the one in the Shadow Moses Island where he can communicate with Colonel Campbell, Mei Ling or Otacon. When he performs the taunt, he hoists his box over his head and hides inside it. Quickly, he will take off the box and throw it aside. If the box hits an opponent when it is thrown, the opponent will take damage. Other players can also pick up the box while Snake is hiding inside it. The Cardboard Box that Snake uses has the "Smash Bros. Emblem" on it with the text "Smash Bros." on it as well as an exclamation mark. Aside from a taunt, it also makes other various appearances in the game for example, it appears as a trophy in the game.
In the Subspace Emissary, the box is first seen after the cutscene where Link and Yoshi chase the Halberd but reach a cliff which stops them. The scene then changes to inside the Halberd, where the box starts moving a bit. However, it isn't until much later that Snake finally comes out of his box and comments that he's been waiting too long. He then travels through the Halberd but he then hides in his box again, trying to hide from Lucario and Meta Knight who just passed by him. Lucario uses the Aura and spots Snake so he takes the box off him and throws it away. The Cardboard Box also appears in the E3 Trailer at the end of the movie. After Colonel calls Snake, Colonel asks him if he's familiar with Smash Bros. Colonel then tells him he has an invitation to join. However, as it turns out, Snake is already in the Battlefield hiding in his box watching his opponents (Link, Mario and Kirby) fight. After a few seconds, he comes out of his box and says "It's show time!"
The box also appears in Super Smash Bros. Ultimate as a novice support spirit.