Lassoo

Lassou used to be Mr. 4's gun before it consumed the Inu Inu no Mi, Model: Dachshund. The fruit gave the gun the ability to turn into a dachshund, becoming literally a dog-gun. The fruit is known as the Mutt Mutt Fruit in the English anime and he is a mixed-breed dog, also called mutt.

Lasso teams up with the Mr. 4 and Miss Merry Christmas team to fight Usopp and Tony Tony Chopper. On Mr. 4's call, Lasso would cough up an infinite amount of exploding baseballs that (to Usopp's surprise) are not balls that explode on impact, but when a timer runs out. According to Chopper, Lasso's baseballs are as heavy as cannon balls, thus ruining Chopper's plan to throw the ball back towards the agents before the baseball explodes. Lasso is ultimately defeated when Usopp tricks Mr. 4 into slugging Miss Merry Christmas with his 4-ton bat. While Mr. 4 was shocked at what had just happened, Usopp took advantage of this time to fire a hammer at Mr. 4's gut using Chopper's horns as a slingshot. Mr. 4 then flies into Lasso and hits a stone structure thus knocking them both out. However, not before Lasso could cough up one last exploding baseball that supposedly finishes off the Mr. 4 team. However, the only thing it does is add more injury to the trio. Lasso is then arrested by the Marines along with the rest of Baroque Works when Sir Crocodile is defeated. After all the members of Baroque Works have been exposed, Miss Goldenweek, Miss Valentine, and Mr. 5 fly to the Marine base and tries to break out all of the captured members of Baroque Works. They succeed in rescuing Mr. 4, Miss Doublefinger, Miss Merry Christmas, and Lasso (Sir Crocodile and Mr. 1 decide to stay behind.) Lasso then helps out around the new Spiders Cafe.

Trivia

 * When Miss Goldenweek uses her Rainbow Colour Trap on Lasso, it is revealed that his dream is to become a tank. Later, when the released members of Baroque works open a new Spiders Cafe, Lasso is shown in his new tank form instead of his old gun form. Despite becoming a dog he still thinks as a weapon, and the wish of a gun would be becoming a more powerful gun.