"colossal length" is correct and can be used in written English.
You can use this phrase to refer to exaggerated or great length. For example, "The great wall of China stretches a colossal length across the countryside."
The Sunday Times's Dominic Sandbrook adopted a rather less subjective approach, calling the author's chronicle of the last eight years of Nelson's life "a sequel of colossal length, global sweep and great psychological acuity … At times his book, almost staggering under the weight of detail, is slow going.
You hear Dylan, who wrote endlessly in the studio while his session musicians napped and played cards, hint at the colossal length of "Sad-Eyed Lady of the Lowlands," the eleven-minute ballad to his wife, when he tells them, finally, "It's two verses and a chorus five times".
Fruit flies (Drosophila) have evolved colossal sperm cells that can reach lengths up to 5.8 centimeters, roughly 20 times the length of its body and about 1000 times longer than a human's.
At 14 metres long it looks colossal – but it's barely half the length of the "white demon" that scuppered the Essex.
The moth is large at around 16cm in wingspan, but the proboscis is truly colossal and can be more than 20cm in length forming a huge coil in front of the head when not in use.
This colossal constrictor measured more than 45 feet in length and tipped the scales at a ton, Time magazine reported in 2009.
Four waist-length black hairdos catherine-wheel in time to colossal riffs, red robes billowing in a backdraft of psychedelic reverb.
When I wrote at length about Cage in 2010, I noted that he accomplished something like a colossal land grab, annexing the entire landscape of sound, from pure noise to pure silence.
O'Shea estimates that a colossal squid's mantle could grow up to 4 meters long, with a possible total length of 12 meters.
The squid -- colossal is its species name, or more scientifically, Mesonychoteuthis hamiltoni -- an estimated 990 pounds and 39 feet long, about the length of a school bus, took two hours to land in Antarctica's Ross Sea.
