In Pokémon Red and Green, Bulbasaur is the starter Pokémon that already has two types: Grass and Poison.
Bulbasaur is one of the three Pokémon offered at the beginning of the original games. Charmander is a Fire type, and Squirtle is a Water type. Bulbasaur’s dual typing gives it a different battle profile from the other two choices and makes it especially effective against many early-game Water- and Rock-type opponents.
The creature also carries a plant bulb on its back. That bulb grows as Bulbasaur evolves into Ivysaur and then Venusaur. Its design combines an amphibian-like body with a large flowering plant, making the Grass/Poison typing visually meaningful.
Pikachu is not one of the standard three choices in Red and Green. It became the player’s partner in Pokémon Yellow, a later game inspired partly by the television anime’s focus on Ash’s Pikachu.