When bonded with Eddie Brock, the symbiote features a mouth with sharp teeth and a long tongue. Also it now has red highlights in addition to the blue highlights.
Spider-Man goes to Dr. Connors to examine his symbiote costume and Conners tells him that the symbiote wants to bond and take over it's host and tells Spider-Man to get it off. In the comics, Spider-Man went to Mr. Fantastic/Reed Richards who said the same thing and removed the suit for the first time in "The Amazing Spider-Man" (Vol. 1) #258.
The idea that the Alien Costume alters its host to be more aggressive is an original idea created for this series.
The ending of the episode is based on "Web of Spider-Man" (Vol. 1) #1 when the alien symbiote costume broke free from 4 Fryeedoms Plaza and rebounded with Spider-Man. In that story Spider-Man was fighting a group of Vulture knock offs in red and yellow costumes called the Vulturians instead of the Shocker.