Yoshi is a friendly creature resembling a dinosaur or dragon, with a saddle on his back that allows him to be ridden by Mario or Luigi. The term "Yoshi" can refer both to an individual character and his species in general. While the "main" Yoshi is a Green Yoshi, the Yoshi species comes in many different colors, which are represented by Yoshi's palette swaps across the Super Smash Bros. series.
Yoshi first appeared in Mario's first Super Nintendo Entertainment System game, Super Mario World. In the game, the player played as Mario or Luigi, and were able to find Yoshi Eggs, which would hatch automatically, revealing a full-grown Yoshi. Later in the game, Baby Yoshis could also be found. The player could grab these baby Yoshis and toss them around like they could with a shell. They could also feed the Yoshi 5 enemies, which would result in the Yoshi maturing, allowing the character to ride the Yoshi's back. Also in the game, 4 different color Yoshis were introduced, each with its own special abilities, depending on what color shell it had in its mouth. The Green Yoshi is the most common found color Yoshi. He grew wings and could fly freely when he had a Blue Shell in his mouth. When he had a Red Shell in his mouth, he could spit fire. Lastly, when he had a yellow shell, he could stomp the ground when he jumped. The color of the Yoshi indicated what his special abilities were when they had a shell in their mouths, matching the colored shells. No matter what shell they had, the Blue Yoshi could fly, the Red Yoshi could spit fire, and the Yellow Yoshi could always stomp the ground.
Yoshi then took the spotlight in Super Mario World 2: Yoshi's Island for the SNES. As the main playable character, Yoshi kept all his previous moves (eating things, pounding the ground) and added a few new ones (using his tongue, egg tossing, flutter jumping). The game was a prequel of sorts to the Mario universe: Baby Luigi was captured by Kamek while being delivered by the Stork, while a group of Yoshis discover the missing Baby Mario and work to rejoin him with his brother.
Yoshi went on to become a mainstay in the Mario series, as well as his own spin-off series.
Main article: Yoshi (SSB)
Yoshi makes his first appearance in a fighting game in the original Super Smash Bros. as a starting playable character. His design is based on his appearance from Super Mario World. As the twelve-character roster goes, Yoshi is arguably the most unique. Not only does his shield (in which he uses an egg rather than the standard bubble that shrinks) not follow the same laws as other shields, but he lacks a triple jump - which he makes up for with a massive and generally safe double jump. These unique points make Yoshi rather difficult for beginners to learn. However, Yoshi makes up for this with his very versatile combo options, such as a forward aerial that can get early offstage KOs and be used in almost any situation, as well as his DJC aerials being very useful for comboing and pressuring. He is ranked 5th on the current tier list, at the bottom of A tier.
Yoshi's in-game description reads:
Main article: Yoshi (SSBM)
Yoshi returns in Melee as a starting playable character. His design is still based on his appearance from Super Mario World. Yoshi stays relatively unchanged, but is given a few new visual properties, such as a more realistic dinosaur posture and several new, unique techniques such as edge-canceled eggs. Although Yoshi can continue to double jump cancel, he was somewhat nerfed; he is now unable to jump out of his shield and continues to lack a third jump, two things that are hard to simply brush off. That said, his unique shield physics, agile yet heavy frame, and powerful attacks are not to be shunned. Yoshi is currently ranked 12th on the current Melee tier list, while he was initially regarded poorly, his position in the current metagame has improved significantly, due to recent high tournament results by particular Yoshi professionals, notably aMSa.
Main article: List of SSBM trophies (Yoshi series)
Yoshis are gentle, fleet-of-foot dinosaurs that make their home on idyllic Yoshi's Island. They come in a variety of colors and have evolved an interesting trait to help increase their numbers: they can transform anything they swallow into an egg. With adhesive tongues and bottomless bellies, Yoshis have been known to eat anything.
Main article: Yoshi (SSBB)
Yoshi once again returns as a playable character in Brawl. He appears in his more recent cartoony stand-up look from the Mario sports and party games such as Mario Party 4 and Mario Kart: Double Dash!!. His moves are relatively unchanged from his Melee moveset, except for the fact that his up special move, the Egg Toss, now acts somewhat as a third jump, which gives him a little extra air/stall time. This is a welcome addition for Yoshi, especially since the directional air dodge seen in Melee has been removed, which previously aided Yoshi in his recovery. He also keeps the unique ability to be able to resist knockback during his second jump. Yoshi is ranked 27th on the current tier list in D tier.
Main article: List of SSBB trophies (Yoshi's Island series)
As a Playable Fighter
Main article: Yoshi (SSB4)
Yoshi returns as a playable character in Super Smash Bros. 4. In this game, Yoshi stands more upright to match more closely to his recent artworks. Yoshi features brighter colors and, from the trailer, seems fairly similar to his past versions. Another notable visual change was to his up special move, the Egg Throw, which now has a rainbow effect to it when thrown.
Yoshi is currently ranked 23rd out of 58 characters on the tier list, settling in D tier. Yoshi has been buffed in the transition from Brawl to Smash 4, with increased speed and utility in his moveset. His KO options and set-ups were also improved. He also regained the ability to jump out of shield, something he could not do since SSB, and his shield drop is also much quicker, giving him better defensive options. Despite being buffed for the better, Yoshi received nerfs to his overall damage output. His grab game is also lackluster, due to his grab having noticeable stat-up and ending lag, as well as weak throws that are generally not reliable enough to KO. His rolls don't travel far too, limiting his escape from pressure. Nonetheless, Yoshi's buffs are significantly enough to increase his viability from Brawl. While having a few notable players, Yoshi does not have many tournament results to speak of, even with his improvements.