In a transparent square glass case, a snail is slowly wriggling.

It is an amber snail, a snail distributed all over the country.

It originally lived in dark and damp places, such as grass, ditches, etc. It not only likes humidity and heat, but also can tolerate drought and cold, and can also do floating movement on aquatic plants and water surfaces, and it feeds on humus, as well as lichens, fungi, mosses, algae, young shoots and young leaves of plants, etc.

The size of the shell of the amber snail varies widely, it is usually oblong-oval, with 3-4 snail layers, the shell is 5-15 mm high, 3-8 mm wide, the chitin is thin, the shell surface is pale yellow or yellowish-brown, and the body is transparent or translucent, and shiny.

But the snail in the glass box, the two tentacles are particularly swollen, compared to the normal amber snail, like two abominable growths.

Moreover, in its transparent body, it is clear that there are some things in it, but not its internal organs.

Suddenly, it squirmed faster, squirming frantically at a speed that a snail would normally hardly reach.

Its two swollen tentacles reflected bright light, like two drill bits, constantly rotating, constantly flickering and changing.

"Students, this is a snail infected with parasites. The colors and lights that you see are actually a lot of parasites wriggling inside it. ”

In the biology class of this university, with the teacher's words, a slow-motion image magnified ten times played on the teaching screen, or this amber snail, and the students saw the creepy details, which were indeed not a natural luster.

It's the snail that's stuffed with parasites, one by one, and they're constantly pushing and jumping.

"That's the double-disc fluke, and they change the snail's body shape and control the snail's brain."

The image on the teaching screen is changed, and the double-disc fluke, a parasite that looks very large under the lens.

Some of these biology students frowned, some were curious, and some had already understood.

"First, the snail ate the eggs of the double disc fluke." The middle-aged man's teacher said, "This is how the parasite enters the host. ”

"The eggs then develop into sporangia, which are mainly parasitic on the snail's liver. At this time, the snail still did not behave abnormally. It may not even know that it has worms in its body, and the nutrients it has worked so hard to eat are constantly being stolen by the parasites. We are not snails, we are uncertain about this, and we don't know exactly how they feel. ”

There was chuckling in the classroom, but the students quickly fell silent.

They looked at a simulated image on the screen, demonstrating how the parasite grows cercariae, then grows, and then branches out of the snail's body into the two antennae, and then forms a complete sporangia full of larvae.

It is they that cause the snail's antennae to swell so much that they cannot contract properly, and can only hang out brightly.

Looking at these pictures, some students really feel that this snail parasitized by the double disc fluke is too pitiful.

"Once inside the snail's eye stalk, the disced fluke begins to have the ability to control the host. Snails originally preferred to be active at night, but when controlled, they become active in daylight, well-lit areas, and move up to three times as fast as normal snails, which may be the physiological limit of snails. ”

The teacher pointed to the diseased snail in the glass box on the podium, its tentacles flashing like neon signs.

"How does Double-Disc Fluke control snails has not yet been studied, students, it will be up to you in the future.

But these parasites are really smart, they make the snail so colorful that it loses its sense of fear, and it swaggers in the sun, which is so eye-catching, and they control the snail to climb up the taller leaves, those particularly conspicuous places. For what? Just so that the birds can see. The birds saw that there was a shiny thing there, and it was in the shape of a bug, so they flew over and ate it in one bite. That's actually a snail's antennae, and it's all double-disc flukes. ”

The teacher paused, picked up the chalk and wrote it on the blackboard, emphatically speaking: "Aggressive mimicry, here is the situation where the parasite benefits." ”

Aggressive mimicry, a biological concept in which organisms use mating promises, false food, etc., to trick their prey into falling for it.

For example, pitcher plants simulate flowers to trap nectar insects. Feeding, surviving, and reproducing, this is the wisdom of nature.

"The snail is the first intermediate host." The teacher wrote on the blackboard as he preached, "Birds are the second intermediate host. After entering the bird's body, the double disc fluke reproduces there, and the eggs are excreted with the bird droppings, which are eaten by other snails...... And so on and so forth. ”

The students got goosebumps as they heard that the disced flukes used snails as fake food and that the prey was birds.

A small parasite, which is only a fraction of a centimeter, has such a sinister and grotesque trick.

And it can distinguish between day and night, high and low, conspicuous and hidden.

Whether it's wisdom or instinct, it's amazing.

"Teacher, can disced flukes control birds?" A male student asked.

"There is no evidence of this."

"Can it enter the human body?"

"It's not a human parasite." The teacher smiled and said, "Our human body is more complex than snails and birds, and we have a stronger defense system to block the double disc fluke." But we also have a lot of parasites to deal with, like nematodes. I know what you're asking, no, there's no parasite that can control human thoughts and behavior. ”

"Maybe there's still one called money." The teacher added, "The English name is Money, and the Latin name is Aes." ”

There was another chuckle of students in the classroom.

It is true that humans are not snails, and parasites are not so easy to control.

And at the same time, in that clear glass box, the snail squirmed and wriggled wildly for a second.

……

Toot toot, toot toot, the call went through.

"Hey, is it Wang Jiawei's mother? I'm Lee Woo-ho's mother. Yes, our son has a dormitory. ”

"Hello Yuhao's mother, what are you looking for me?"

"That's right, Yu Hao told us last night that he and a few classmates went to your house to have a party and spend the night there. I called him in the morning, but no one answered, and now it's almost noon, and still no one answers, and he hasn't come home yet. I also have Jiawei's number here, and there are a few other classmates, I called them, but no one answered......

"Is that so...... Yuhao's mother, Jiawei and my father are out of town these days. Don't worry, young people must have a party late, and they don't have to go to school today, and it's not surprising that they have stayed up all night, maybe they haven't woken up yet, and no one answers. ”

"I thought so, too, but it's always a little weird...... None of these children posted on Moments, which of the previous gatherings did they not post a few messages? ”

"Hmm...... Otherwise, I asked the community property management to send someone to my house to see what the situation is, maybe drunk? ”

"Okay, Jiawei's mother, I'm sorry for you."

"Hey, what's welcome, this is also Jiawei's party."

The call is over.

Less than half an hour later, the call was connected again.

"Hey, Yuhao's mother? Just now the security guard went to see, no one was at home, and found that my garage was open, I looked at the picture, and there was an MPV that was driven away. I asked the security guard to check the monitoring of the community, the car was driven out last night, Jiawei's car, Yuhao and they were all in the car......"

"What...... Can Jia Wei drive? This, where did they go? ”

"I don't know here, Yuhao's mother, it shouldn't be fine, the young man is just going crazy, let's not mess up."

"Don't say it, call the police, let's call the police quickly."

"Wait, this hasn't come to that point yet, don't make a big deal about it just yet...... Yuhao's mother, don't look at the car driven by Jiawei, you think that I only think about my son. What if all of them were the ones who did the bad deeds? We don't know, I mean, if they touch marijuana, ecstasy, or anything like that, calling the police is ruining them, and we have to think about the children. ”

"Hey! You're ...... Isn't it our first priority to think about whether they are safe now? My family Woo Hao is not the kind of person who can touch drugs. ”

"I'm making an analogy, slow down, Yuhao's mother, look at the circle of friends! I saw that Jia Wei just posted a circle of friends. Do you see if Yu Hao has sent it? ”

"Ah, let me see, hey, yes, yes, yes! Yu Haogang also posted one. This kid is here, why don't you answer the phone? I didn't call back to report a letter, it scared me to death, hey, really. What does this circle of friends mean...... 'I have seen God, and I am His embodiment in the human world. ’”

“…… Jia Wei also posted such a sentence, did they go to any concert to see which idol? ”

"Probably, kid...... Jiawei's mother, that's the case first, I'll call Yu Hao again, and when he comes home, see if I don't smoke him. ”

"Young people don't need to be beaten and scolded when they go crazy, but this Jiawei, I'm going to clean him up when I go back."