Salvo the Slime is a boss appearing in the Yoshi series whom is a type of slime.
Super Mario World 2: Yoshi's Island
When encountered by Yoshi in Super Mario World 2: Yoshi's Island, he began as just a regular little Slime, but Kamek enlarges him until he is several times bigger than Yoshi. Salvo can't directly hurts Yoshi but instead pushes him along.There is lava under the room, with a hole at one end that Yoshi risks falling in; Salvo never falls down the hole. Whenever Salvo is hit by an egg, he gets slightly smaller and several regular sized Slimes, which Yoshi can eat to produce eggs. If left for long enough the Slimes will wriggle into the hole and fall into the lava. Bit by bit Salvo gets smaller and smaller until he bubbles down to just his eyes, which pop. Yoshi then goes to the next world.
Later on in the game in another bosses castle, Yoshi must get a key. To get the key he must go to a room were he must fight a slime similar to Salvo. When it is defeated it bubbles down in a similar fashion to Salvo before the keys come out. He must fight at least two of them. This time however, smaller Slimes are not created, and they must be careful to make sure their egg rebounds and hits the slime more than once.
Mario Party Advance
Salvo reappears in Mario Party Advance as the second boss in the Duel Tower. He challenges the player to the minigame Volleybomb and the player obtains the minigame it he/she completes it.
Salvo makes a cameo in Yoshi's Island DS in the opening of the game along with the other bosses from Super Mario World 2: Yoshi's Island.