Rope Snake

Rope Snake (Japanese:  Rope Snake) is a character in Mother 3 and Super Smash Bros. Brawl.

In Mother 3
Rope Snake is owned by Duster, being first bought from a ghost in Osohe Castle in Chapter 2. Rope Snake can grab onto various objects and act as a tether, capable of supporting Duster perfectly fine. However, it is shown multiple times that Rope Snake cannot support the weight of three people and a dog, accidentally dropping Lucas and his party twice.

Memo
"He makes a cute pet, but he acts like a rope, so he'll surely be useful on your adventure."

In Super Smash Bros. Brawl
In Super Smash Bros. Brawl, the Rope Snake is used by Lucas to grab opponents, and can also be used as a tether recovery.

In Super Smash Bros. 4
The Rope Snake was announced in the Nintendo Direct for April 1, 2015. The DLC it will be in along with Lucas is planned to be released June 2015.

Trivia

 * The Whip in The Legend of Zelda: Spirit Tracks is a red, snake-like item which functions very similarly to the Rope Snake. Eiji Aonuma confirmed that the Rope Snake was the inspiration for said item.