After accepting Professor Rowan's request, Rex wasted no time and immediately began investigating the cause of the Ariados infestation.
Ariados has a spider-like appearance with a head and abdomen. Its red head has a single horn, purple eyes, and a red and black abdomen with two pairs of yellow and purple legs. There are two black spots on its rear abdomen, each with a yellow horn.
Ariados doesn't build webs in a fixed place. Instead, it waits for darkness to fall before searching for food. It always leaves a special thread from its rear, which it can follow back to its nest. At night, it leaves the nest to actively hunt.
Rex knew that Ariados is the evolved form of Spinarak. The fact that Ariados was swarming meant that a massive number of Spinarak had also arrived in the area.
Professor Rowan wanted Rex to solve the Ariados infestation, not by killing them, but by figuring out why they had migrated to the outskirts of Sandgem Town.
Only by finding out the reason for the migration could they help the Ariados return to their original territory and restore peace to Sandgem Town.
However, Rex had no leads, so he decided to first ask some locals about the situation.
Suddenly, Rex thought of someone—Officer Jenny of Sandgem Town. As the town's police officer, she would likely know the most about the Ariados infestation.
Using his phone's navigation, Rex quickly found the town's police station.
Although Sandgem Town's population was similar to Fallarbor Town's, its police station was not as shabby. Rex figured this was due to Professor Rowan's research lab being located here, leading the Pokémon League to station more police forces in the town.
After all, any research at Professor Rowan's lab would be incredibly valuable, and strengthening the town's defenses would be wise.
"How can I help you?" a sharp-looking policewoman asked, stopping Rex.
"I'm looking for Officer Jenny. Could you please introduce me?" Rex replied.
"Oh, you're looking for the chief. She's in her office. I'll take you there," the policewoman said, leading Rex into a spacious room.
Inside, Officer Jenny was busy working on her computer. However, when she saw Rex enter, she stopped what she was doing and gestured for him to explain why he had come.
"Officer Jenny, my name is Rex. I've been entrusted by Professor Rowan to handle the recent Ariados infestation near Sandgem Town. I'd like to ask for your assistance," Rex said, explaining his reason for visiting.
"Of course! These Ariados have been causing a lot of trouble for the townsfolk. If you can resolve this issue, that would be wonderful!" Officer Jenny responded enthusiastically.
In recent days, many Ariados and Spinarak had suddenly appeared on the outskirts of Sandgem Town. They had already clashed with the residents multiple times. Although no one had died, several people had been injured.
Moreover, the farms outside Sandgem Town were frequently attacked by the Ariados, causing severe losses for the farmers.
Officer Jenny had organized several clean-up efforts, but the Ariados were crafty. When outnumbered, they would quickly flee. In the forest environment, they could disappear without a trace, making it impossible to track them.
Officer Jenny had just been writing a request for help, hoping the League would send a skilled Trainer to handle the situation. But with Rex, who was sent by Professor Rowan, she decided to hold off on asking for League reinforcements.
It wasn't that she trusted Rex; it was that she trusted Professor Rowan's judgment. If the professor entrusted Rex with this task, it meant Rex had the skills to resolve the situation.
Officer Jenny then shared all the information she had about the Ariados.
According to her, the Ariados had appeared about a week ago on the outskirts of Sandgem Town. Their main activity area was in the small woods Rex had passed through earlier.
However, the food in those woods was clearly insufficient for the Ariados, so they often raided nearby farms at night.
As for where the Ariados came from, Officer Jenny speculated that they had migrated from the primeval forest between Sandgem Town and Twinleaf Town.
Since Officer Jenny couldn't provide more information, Rex decided to get the truth from the Ariados themselves.
Leaving the police station, Rex returned to the small woods where he had been attacked by Ariados. He planned to capture a few Ariados and use Haunter's Hypnosis to uncover the reason for their migration.
Rex wasn't worried about being attacked again. Ariados are vengeful Pokémon, and if he showed up, they would surely attack in greater numbers.
Sure enough, not long after entering the woods, Rex felt several eyes watching him. The further he went, the more intense the stares became.
Finally, an Ariados launched an attack, firing Poison Stings at him. Haunter, hiding in his shadow, jumped out and used Shadow Ball to deflect the stingers.
Rex found himself surrounded by Ariados and Spinarak, with the leading Ariados eyeing him mockingly as if he were easy prey.
But Rex remained calm. He released Combusken and ordered it to use Flamethrower on the leading Ariados.
The intense flames panicked the Ariados, but they still attempted to extinguish the fire with Poison attacks, believing their numbers would prevail.
Unfortunately for them, Combusken's flames were stronger than expected, breaking through their defenses and striking the Ariados.
Several Ariados were knocked out on the spot. Seeing they were outmatched, the remaining Ariados tried to retreat, but they didn't forget to drag their unconscious comrades with them.
Rex wasn't about to let them take the fallen Ariados. He quickly captured two of them with Poké Balls.
Seeing their comrades captured, the remaining Ariados had no choice but to disappear deeper into the forest.