Today’s device from William Packard’s The Poet’s Dictionary: A Handbook of Prosody and Poetic Devices is

Oxymoron:  A radical paradox; a conjunction of extreme opposites.  “Dry ice is so cold that it burns” is an example of oxymoron.

In poetry, oxymoron also functions metaphorically (see METAPHOR) to express a state of ambivalence or contradiction. …

Old Lamb
(by Suzanne Baldwin Leitner)

“What did the tired nurse
say to the complaining
patient?
‘Take your Oxy
Moron.'”

And that’s what
every interminable
minute was like
with him: a slow
trot from one
sad joke
to the next.