When I encounter the adjective 'sfnal', I usually misparse it as a noun, then have to back up and reread the phrase it's in once I realize I've got the wrong part of speech.
OT1H, I think I know why this happens -- I think I'm latching onto that '-nal' ending and associating it with church ...
OTOH, that doesn't happen with other, longer words that end in '-nal' ...
OTGH, at least the alternate meaning my brain supplies -- a book of filk music -- can at least be possibly considered sfnal itself.
Translation available on request, but it's more fun this way.