Princess Spikyback

Princess Spikyback is Carson Mackenzie's pet iguana.

She allows Princess Spikyback to roam around the apartment, which has caused Lizzie many a startled moment.

Lizzie Brooks
Lizzie is very fond of Carson's pet iguana. She is introduced to the Princess soon after meeting her new roommate... that is, she finally gets to see Carson's room and sees Princess sitting on Carson's bed. "That explains so much about her." Once, Lizzie steps into the shower to find Princess Spikyback in it. She screams.

Blair Moore
''Blair stared at the lizard. The lizard stared back. She turned to Carson. "So do you feed her...like, bugs or something?"''

(This is gist of Princess Spikyback's entire interaction with the whole cast. Occasionally, Princess Spikyback turns her head slightly.)