Ivysaur is a quadruped Pokémon similar to a dinosaur. It has blue-green skin with darker patches. On top of its head are pointed ears with black inside, and it has narrow red eyes. It has a short, rounded snout with a wide mouth. Two pointed teeth protrude from its upper jaw. Each of its feet have three claws on them. The bulb on its back has bloomed into a large pink bud. A short brown trunk surrounded by leafy green fronds supports the bud. The weight of the plant prevents Ivysaur from standing on its hind legs and forces its legs to grow sturdy. When its flower is ready to bloom, it gives off a distinct, strong sweet-smelling aroma and starts swelling. Ivysaur will also start spending more time in sunlight in preparation for its upcoming evolution. Exposure to sunlight adds to the strength of both Ivysaur and its plant. Ivysaur's natural habitat is plains. However, it is rare, as many are in captivity.
Ivysaur appears to be based primarily on some form of reptile, specifically mammal-like reptiles known as Dicynodonts from the Permian period. Along with visible ears and no genuine metamorphosis stage (evolution aside), Ivysaur appears to have more in common with mammals than amphibians such as frogs and toads, which metamorphose from one definite creature into another as they mature as opposed to just growing into a larger adult version of itself the way that Bulbasaur does. Alternatively, Ivysaur's large rounded snout, wide mouth, wide-set eyes, blotch-patterned skin, and quadruped-like movements are vaguely similar to those of certain amphibians, such as the common toad. Unlike Bulbasaur, Ivysaur's "ears" do have hollows indicating that they are in fact ears and not glands, as seen in many species of frogs and toads.
The bulb on its back now resembles the bud of a genus of parasitic flowering plants known as Rafflesia.