Were the Skrulls hard to deal with? Not really. As it turned out, Harry had greatly exaggerated their abilities.
Of course, it was also possible that this batch of Skrulls had been weakened. They were nowhere near as formidable as in the comics, where they could even copy abilities.
Skrull cells rapidly stripped genes from the cells of those they imitated, then used those genes to replicate cells and proteins, perfectly mimicking the target.
After extensive research and comparison, they finally discovered that cells produced through Skrull mimicry had abnormally short telomeres.
Although they were much shorter, that was only relative to normal telomeres, making them difficult to identify. But when Black Water came into contact with these "fake genes," the overly short telomeres could not remain stable and would collapse.
Mimicry rapidly consumed a cell's potential, causing telomeres to shorten quickly. The cells produced by their special cells possessed exceptionally short telomeres, and the difference in length was difficult to detect.
That was why Skrulls needed to constantly replenish their genes to maintain their disguises.
After understanding this, Harry roughly guessed how Mister Fantastic had exposed the Skrulls in the comics. If they could create a device that released telomere-wearing radiation after firing, those Skrulls would revert to their true forms.
And Reed happened to have undergone the strangest change—he could alter his body at will, so he could not have known more about this kind of thing.
So "intelligence" really was something mystical here... The Kree had fought the Skrulls for centuries without finding a way to identify them, yet Reed had casually cobbled one together in the comics.
Harry did not have those conditions now. A weapon that damaged telomeres would not be difficult to make, but it would obviously be just as devastating to Earthlings and