Robin Spencer (also known as Stainless) is the main antagonist of the Fillmore! episode "To Mar A Stall". She was the President of the X Middle School Bathroom Steering Committee until her dismissal.
She was voiced by Mae Whitman.
Robin first appeared cutting the red ribbon for the girls' new restroom as she ordered new stalls to be implanted. However, the ceremony went wrong when everyone found out that the walls and stalls have been vandalized with the word "STAINLESS" in red paint, prompting a shocked Robin to faint in horror.
Patrol safety officers Cornelius Fillmore and Ingrid Third were called in to investigate the situation by interrogating Randall Julian, who was once a tagger himself as he vandalized every bathroom in the school (except for the one in the teachers' lounge). Julian explained that the "Stainless" tagger is left-handed and only writes backwards because writing forward would only leave smears on it.
Fillmore and Third managed to catch a kid named Tommy Howard, who claimed credit for vandalizing the bathroom, but it turns out that Tommy was only stealing black markers and that he only took credit for the tagging just to become famous. Fillmore and Ingrid then checked to see that the boys' bathroom has been vandalized as well, just as a hooded figure sets one of the toilets to project the water towards them before escaping.
Though it would have seemed that Fillmore and Ingrid are out of their wits, they were given a copy of the school newspaper with a photo of Robin by Randall at the ceremony. Noticing that Robin is wearing a glove while cutting the ribbon, Fillmore and Third soon learned that she placed an order brushed steel stalls 43 times, only to be ignored. They soon realized that Robin is the true tagger as she vandalized the original stalls to replace them with the new ones.
With that in mind, the two confronted Robin for her actions and pulled off her glove, revealing a small amount of red paint in her wrist. Realizing that she's been exposed, Robin tried to make a clean getaway, but she is caught by Fillmore using Vallejo's new fishing rod and bubble wrap. With her villainous actions exposed, Robin is sentenced to either detention or suspenion as punishment for her crimes.