After leaving Magnetic Storm Canyon, they walked for about half a day before hearing the sound of water.
"Water?" Gon pricked up his ears. "It's a river!"
He quickened his pace and passed through a stretch of low Stone Forest. The view suddenly opened up before him.
An underground river stretched across their path. It was dozens of meters wide, with a gentle current. The water was warm, giving off a faint mist. Glowing ore on the riverbed illuminated the water pale blue, like a flowing ribbon of light.
"An underground river." Kurapika crouched down and touched the water. "The temperature is suitable. There should be fish inside."
"Fish?!" Gon's eyes lit up instantly. He yanked off his backpack and pulled out the fishing rod made from Steel Bone Fish vertebrae. "It's finally going to be useful!"
Killua skated to the riverbank and looked over the water.
"This water looks pretty deep," he said. "And... there's something in it."
The instant he finished speaking—
"Crash—!!!"
The river's surface exploded, and a massive head rose from the water.
The head was as large as a truck, covered in thick rocky armor. Its mouth was filled with dagger-like fangs, and its two small eyes glared viciously at them.
The Rock-Shell Giant Crocodile was a Level 140 monster and the ruler of the underground river. Its hide was thick and its flesh tough, while its bite could crush steel.
It swept its gaze over them and let out a low growl before diving back into the water. The river's surface returned to calm, leaving behind only rings of ripples.
"Level 140..." Leorio swallowed. "That's five levels higher than yesterday's Crystal Armor Beetle King."
"And it's in the water." Kurapika frowned. "In the water, its combat power increases by at least thirty percent. We'd