‘Bathos is a tradition from the dignified or grand to commonplace or laughable; an anticlimax […].'[1] The term was first used in this sense by Alexander Pope in his treatise Peri Bathous; or, The Art of Sinking in Poetry (1728).
From the Ancient Greek βάθος meaning ‘depth’, bathos is generally a sudden change of tone in a work of writing, usually from the sublime to the ridiculous. When used unintentionally or executed poorly, this may result in sappiness. When used properly, this may create a comedic effect.
Bridgekeeper: Stop. Who would cross the Bridge of Death must answer me these questions three, ere the other side he see.
Sir Lancelot: Ask me the questions, bridgekeeper. I am not afraid.
Bridgekeeper: What… is your name?
Sir Lancelot: My name is Sir Lancelot of Camelot.
Bridgekeeper: What… is your quest?
Sir Lancelot: To seek the Holy Grail.
Bridgekeeper: What… is your favourite colour?
Sir Lancelot: Blue.
Bridgekeeper: Go on. Off you go.
Sir Lancelot: Oh, thank you. Thank you very much.
– Monty Python and the Holy Grail (1975)
[1] Fiske, Robert Hartwell (1 November 2011). Robert Hartwell Fiske’s Dictionary of Unendurable English: A Compendium of Mistakes in Grammar, Usage, and Spelling with commentary on lexicographers and linguists. Scribner. p. 71
Knowledge Guild 
Having nothing to do with Bathos, and everything to Monty Python, this will always be my favorite scene:
“‘Tis but a scratch —”