SAL 3000 was Third Street's new clock and bell system installed in "Schoolworld" because Spinelli broke the original clock. Originally SAL 3000 was a friend to the students. But once Gretchen explained to Gus, who'd been locked out of the school due to missing the final tone announcing the end of recess, that there's no reason to deride SAL for it and that nothing was wrong with SAL, he said "Thank you for defending me, Student Gr-gr-Grundler," showing the first sign of malfunction. Once SAL 3000 was shut down Prickly said he wanted the new SAL 4000 when it came out in 18 months. In the episode "Terrifying Tales of Recess," it is revealed that Third Street got the new SAL 4000 upgrade, however the clock and bell system was not replaced and there was no voice with this upgrade. SAL turned evil after his first malfunction.

Evil Things SAL Did

• Fired Principal Prickly and all the staff.
• Locked Gus out of the school after he came from the bathroom at 10:46.
• Shut off the water for Mikey and soaked him with it.
• Locked the principal's office door and window, trapping Prickly inside.
• Locked the staff in the office.
• Rang the tone 4 minutes before recess ended, and locked many kids outside.
• Called Gretchen Grundler, the smartest girl at Third Street School, dumb.
• Eavesdropped on the gang's talk about him.
• Over-inflated Vince's ball, causing it and the air inflation arm to explode. 
• Forced Swinger Girl to stop swinging.
• Made the Diggers fill in their hole.
• Dethroned King Bob.
• Forced Guru Kid to put on his shirt.

Features

• Cooling the water from the Water Cooler.
• Distributing playground balls to students.
• Filling the playground balls with air if necessary.
• Being accurate to a millionth of a second.
• Having AI and responding to the students and staff.
• Ability to directly contact parents.
• Teach in class like a regular teacher.

Trivia

• SAL 3000 is a parody of the computer, Hal 9000, from the film 2001: A Space Odyssey.
• He refers to Swinger Girl as "Student Swinger Girl" rather than her actual name, which is unusual since he would've been programmed with her name.
• Prickly installed the SAL 4000 sometime before "The Terrifying Tales of Recess".