Are you ready, kids? I can't hear you...
"Attack of the Giant Robots" also plays in "Frozen Face-Off", when SpongeBob saves Squidward.
I think "Xylophone Phrase 2" plays in "SquidBob TentaclePants". I also think it is played in 3 different pitches in that episode.
Which scene? If you're referring to the part where Sandy uses the molecular separator ray, I used the Audacity "karaoke" method to remove the dialogue and all I hear are three woodwind trills with no xylophone.