The Gay, Lesbian and Straight Education Network (GLSEN) have a bone to pick with Nelson Muntz, Bart Simpson’s animated bully, for the character’s “That’s So Gay” slur on The Simpsons annual Treehouse of Horrors Halloween Special last Sunday.

(Fast Forward To 15:45)

In a statement to TMZ, GLSEN said: “Nelson’s use of ‘that’s so gay’ in a negative way is not surprising considering that 90 percent of lesbian, gay, bisexual and transgender youth say they hear the term used this way frequently or often at school.”

“Nelson should visit ThinkB4YouSpeak.com where he can send an apologetic e-card to Milhouse. GLSEN would also welcome Nelson’s participation in our next PSA so he can make amends by helping to educate young people about why such language is wrong.”

The group recently joined forces with the Ad Council to produce a series of public services announcements, featuring celebs like Hilary Duff and Wanda Sykes, aimed at stopping people from using the phrase.