Webber is a spider who is a common enemy in the Wario series. In the original Wario Land, he simply attacks by running in to Wario, but in the sequel, Wario Land 3, he has upgraded to a cannon on his back that lets him shoot projectiles.
He is also the 3rd boss in Dr. Mario 64's Story Mode. After the player passes Rounds 1 and 2, Dr. Mario & Wario will keep chasing the Mad Scienstein through Webber's dark forest. If the player is Dr. Mario, Webber will first grab Wario from above, then do the same to Dr. Mario, who Webber wants to eat as a "nice snack", and the battle begins. However, if Wario was the player's choice, then Wario would be chasing the Mad Scienstein, with Dr. Mario behind (but off-screen), until the scientist suddenly stops, and an unwarned Wario slides right by and gets stuck on Webber's web. Webber then says Wario doesn't look very tasty, and the two battle.