Goodra is most likely based on the Lou Carcolh of French mythology, which is essentially a mix between a dragon and a mollusk.
Goodra's retractable horns may be inspired by the "blue dragon" sea slug's ability to retract it's eyes whenever it is in danger.
Goodra has received generally positive reception for it's adorable appearance and friendly personality.
Many fans are also fond of it being one of Ash Ketchum's strongest Pokémon in the anime, but most were not pleased when Goodra left Ash. Eventually, many rejoiced when Goodra was confirmed to return to fight in the Kalos Pokémon League with Ash.
Goodra has mixed reception competitively. Since weather has been nerfed, along with an increase of Taunt users, it became rather tricky to use defensively. It can also run an all-out attacking set with an Assault Vest equipped, giving it some great Sp. Def in battle.
It can also learn a diverse range of attacks as a fully evolved Pseudo-Legendary. It can learn moves like Draco Meteor, Earthquake, Sludge Wave, Fire Blast, and Muddy Water.