Mermando is a beautiful merman who became stuck at the Gravity Falls pool.
He was swimming with his friends, the mighty dolphins, in the Gulf of Mexico, when he was ensnared in a net by an old, sea captain and a ship mate.
The captain announced they would feast on his flesh and had a truck take him to the Bait Shop at Lake Gravity Falls. He managed to escape as the truck was parking and jumped into the lake. He tried swimming against the current and up a waterfall, but failed when a log crashed into him in the face, in the process loosing a front tooth. He ended up flopping onto the ground, but luckily the local wildlife were kind (or hungry) enough, that they kept licking him, keeping him hydrated. Unfortunately the licks that were keeping him alive were also ticklish and he stumbled into a water drain that led to the Gravity Falls Pool. For an undetermined amount of time, he was trapped there, hiding his secret and unable to get home, until he met Mabel.
On the hottest day of the Summer, Mabel met Mermando on the pool's opening day. Mermando found her charming and forward and took a liking to her. After their first meeting, Mabel asks him out on a date, and that night she meets him at the pool. Mabel attempts to kiss him by puckering up, much to his confusion.
Mabel agrees to help Mermando return to the sea and sneaks into the pool again by taking the Mystery Cart there, where she loaded the back with the Pool's cooler, and filled it with water. Mermando gets in and hides, while Dipper attempts to get Mabel to return the cooler. With a little distraction, Mabel and Mermando make their escape to Lake Gravity Falls. Unfortunately the cooler springs a leak, and Mermando, so close to the water, nearly suffocates to death. Mabel convinces Dipper to give Mermando "reverse CPR," which he reluctantly does.
Now safely returned to the water, Mermando thanks Mabel and Dipper for their help. While bittersweet, Mabel is glad he would be able to return to his family (and gives him the Pool's megaphone as well, to call out to his family). As a farewell gesture and an expression of his own feelings, he gives Mabel her first kiss. Memando is happily reunited with his family, but continues to send Mabel many messages in bottles which end up at the Pool.
Mermando is a beautiful merman with a vivid green tail that is darker towards his waist and lighter towards his tail-tip, and a pink seashell necklace hanging around his neck. He is Hispanic with dark skin and long, wavy, shiny brown hair, and tiny mustache hairs under a long nose. He has a missing front tooth that was lost when he was first trapped at the pool. He has a deep and masculine voice, with a Spanish accent, and speaks with a dramatic eloquence. Being a merman, he has approximately seventeen hearts.
Mabel Pines Mermando is in love with Mabel as to on the characters responces to the winner of the "Gravity falls coloring contest" Mermando said that the winner was as talented as his "Beautiful and sweet Mabel" Therefore Mermando has feelings for Mabel, more likely sends many bottles to her to keep in contact.
Mermando is described as a loner, due to not wanting others to know of his nature as a merman, though enjoys having fun with those who know of his true form. He is polite with an easy sense of humor, often making self-deprecating comments. He tends to be dramatic, often playing his guitar for effect. He is very close with his family and loves them very much, and he nears depression when separated from them. He tries to be optimistic and is easily impressed and persuaded.
As a merman he can swim very well, but cannot survive long outside of water. He can play the guitar and is multilingual, able to speak English, Spanish, and dolphin.