More properly, "Metric Fucktonne." The Fuckton is the Imperial standard for the measurement of fuckweight, while the Fucktonne, in contrast, constitutes the Metric measure of fuckmass.
Generally used to imply superlative quantity with the Metric standard included to emphasise this point. The inclusion of the term is, however, fundamentally a misuse of that standard, as the Imperial Fuckton (2000 Imperial Fuckpounds) denotes a slightly greater measure of fuckweight within Earth's gravitational pull than does the Metric Fuckton (1000 Metric Fuckilograms).
I've got a Metric Fucktonne of this stuff to finish before Monday, or I'm fucked indeed.
Prices shown in USD.