The story
From the fictitious rock band Spinal Tap, as depicted in the mockumentary film This is Spinal Tap (1984).
Etymology from Wiktionary, CC BY-SA 4.0.
Spinal Tap-ian
Today it means: Of, pertaining to, or resembling the fictitious rock band Spinal Tap, especially with respect to its excessive behavior, its very high turnover of members, or its use of sound amplifiers with a maximum setting of 11 (instead of the usual 10). Full definition →