Summary
'Ghost Fight' is a relatively prolific leitmotif that appears throughout Undertale, and gets a cameo appearance in Deltarune.
The motif is split into three distinct parts:
('Ghost Fight' A, B, and C, as heard in Ghost Fight)
Additionally, the motif has an accompanying backing:
('Ghost Fight Backing', as heard in Ghost Fight)
And bassline:
('Ghost Fight Bassline', as heard in Ghost Fight)
Lastly, although not expressly related to 'Ghost Fight', the page will also cover a very minor ghost-related motif, 'Spooktune':
('Spooktune', as heard in Spooktune)
(If you're looking for the quotes of Dummy! in BIG SHOT, see 'Spamton')