Kreptism
To go into an autistic outburst of singing (or texting) lyrics from a random song for no apparent reason.
P1: HASHIRE SORI YO KAZE NO YOU NI TSUKIMIHARA WO PADORU PADORU!!!!!!!!!!!!
P2: Oh god he's having another Kreptism outburst...
P2: Oh god he's having another Kreptism outburst...