Q: "Did you make up named spells like Melf's acid arrow, Otiluke's resilient sphere and Mordenkainen's disjunction yourself, or did these come from player research?" Gygax: "All of those spells I made up, usually to honor a PC in my campaign, or for the person who suggested the basis. Tasha [Tasha's hideous laughter] was a little girl who sent me letters in crayon, Nystul [Nystul's magic aura] was an actual stage magician I met through Len Lakofka. Melf [Melf's acid arrow] was a PC of son Luke, and Otiluke [Otiluke's resilient sphere] was a combination of a couple of his other PCs." "Gary Gygax: Q & A (Part III, Page 6)". EN World. 2003-05-02.
