Sockop

Sockops are sock-like pitcher plant enemies encountered in Dimble Wood during the events of Mario & Luigi: Bowser's Inside Story. They enjoy eating Attack Piece Blocks, and are capable of swallowing humans as well. If Mario or Luigi tries to jump on them, he is sucked into the hole on the top of the Sockop's head. The player then has to mash or  repeatedly in order to escape, otherwise, the brother may be damaged or poisoned. They attack by tackling the brothers. Normally, they run at one brother, then turn around and run at them again. However, if some honey comes out of the top of them, they charge at the first brother and go offscreen, coming back to hit the other brother from behind. They can also steal some of the Bros.' HP and heal themselves with it. Later in the game, Mario is captured by the Sockops and Luigi has to rescue him, getting stuck inside a Sockop in the process. While he is stuck inside the Sockop, Luigi can communicate with them, and doesn't have to fight them. He can also traverse the bramble patches spread throughout the wood. They have a boss - one giant Sockop that is shrunk down to normal size during the events in the game. This aforementioned boss is the Sockop that Luigi ends up using as a "puppet".

Trivia

 * Sockops are similar to the Kuribo's Shoe, a power-up found in Super Mario Bros. 3. One of the Sockops is even revealed to be named Kuribo.
 * At a certain point, it's even used to ride and hop on thorns.
 * Sockops are one of the few non-boss enemies that are known to speak.
 * Sockops are based on a pitcher plant, a type of carnivorous flower.
 * Sockop is a pun of the dance "sockhop".