Bordering On Madness
As observed earlier, the mutated animal was already on the brink of breaking through.
Its beast core was nearing its complete evolution.
Being viciously struck by the lighting strikes from the world's energy, weakend its physique—but that energy also provided stimulus to slowly morph the beast core inside of it, and now, it was already completed.
Under the guidance of the last lightning strike, the beast core shone with a blinding light.
A metamorphosis to its higher form, bringing the mutated animal to the tenth-rank realm.
Just an utter and complete bad luck.
Rex only needed one more hit to completely shatter the beast core—or at least damage it to the point that halted the mutated animal's ascent to the tenth-rank realm. But—his path was intercepted by a lightning strike that was faster than even himself.
Tanking the lightning strike, he was severely injured.