When it comes to youkai humans find unpleasant, Wriggle Nightbug is a good example.

As to why she's considered unpleasant, she always appears with a large number of bugs and can control them at will.

Just imagine being simultaneously attacked by centipedes, caterpillars, moths, spiders, and cave crickets.

It makes your hair stand on end.

This youkai appears similar as a human child.

Fortunately, she doesn't look completely like a bug. She only has antennae and wings but other than that, she doesn't look any different from a human (*1).

Wriggle is a bug youkai, but to be exact, she's a firefly youkai.

Fireflies, unlike most bugs, are popular with humans.

Since this type of bug can avoid being exterminated by humans, it's easy for them to mature into youkai.

In addition, butterflies are similarly quite popular with humans, so it's easy for them to become youkai.

Long ago, bug youkai were equal to oni and tengu in terms of inspiring fear, but lately they've lost that prestige.

The fact that this bug youkai, who could be called the bugs' leader, has the appearance of a young girl could be considered a symbol of this.

The reason why the bugs' power has radically declined needs to be investigated.

1: She likely needs to take on a human shape in order to make it more difficult for humans to exterminate her.

"I lifted up a big stone and there were a whole bunch of bugs under it. It was gross." (Anonymous)

This may not have much to do with this youkai, but it's technically a report regarding bugs.

"There were a clump of centipedes under the overhang of my roof. I wish they'd go away." (Anonymous)

This may not have much to do with this youkai.

"There was a cave cricket at my back door. I hate those things." (Anonymous)

This has nothing to do with this youkai.

The thing that makes bugs frightening is their numbers.

Individually they don't have much power, but when they come in large groups they're hard to deal with.

This is particularly true for bugs such as hornets; while killing one or two means nothing, if they land one sting it can kill a human.

The most effective countermeasure is building a fire and using fumigation in order to keep bugs away from a large area (*2).

Also, they're generally weak to the cold.

They're active from spring through fall, but they almost never show up during winter.

Although her control of bugs is frightening, there isn't much that is dreadful about facing Wriggle Nightbug herself.

If you're trying to exterminate youkai, your best bet is to go after this youkai during winter when she's alone.

Also, among the bugs that this youkai uses, the ones you need to be most careful of are the harvest mites.

Harvest mites are devil bugs that can't be seen by the human eye, and you don't even notice that you've been bitten.

Later, small black bite marks will appear, but by then it's too late; you'll get a high fever and collapse, and there is a high probability of death.

There is no effective treatment.

If Wriggle doesn't seem to have any bugs with her and yet looks highly confident, that is when she is the most dangerous.

She could have harvest mites lurking around her (*3).

2: Recently, there's also a convenient chemical known as insecticide.

3: Or maybe fleas.