According to Gnomic Negotiations, Gnomalus was (and may still be) Head of Psychology at the Gnome Institute of Knowledge, a scientific research organisation based in the Tree Gnome Stronghold. In the book, Gnomalus holds a brief interview with a human negotiator concerning the psychological behaviour of gnomes and humans.
During the interview, Gnomalus points out that, while gnomes possess a natural sense of humour, they also can be serious. Shortly after he makes this comment, it is revealed that the Gnomalus being interviewed was in fact a synthetic replica made by Gnomalus himself. Its head explodes before Gnomalus comes out from hiding, laughing at the practical joke. The interview ends afterwards.