Wordplay:

cadillac attack

a tacky black
bric-a-brac
hacky sack jack
cracked a track
along its back
with a clackety-clack
it hacked
and packed
and stacked
and whacked a pact
with alacrity shacked
it smacked
and snacked
and sneered right back
as a matter of fact
it was
a cadillac attack

—
temet nosce