Teachers reveal the moment they knew their students were trouble.

There are many behaviours children display that are innocent yet inappropriate.

Most can be chalked up to the ignorance of youth, but there are some actions that push the boundaries of ‘should have known better’ to become something else entirely.

Teachers have come forward to share their tales of times when children have displayed antisocial behaviour too extreme to miss.

The tales were exchanged on anonymous forum Reddit after one user posed the question: ‘Teachers of Reddit, what has one of your students done, that convinced you they were a villain in the making?’

Liars

“Lied to me about not finishing a project by saying her mother had terminal cancer. My dad died of cancer when I was her age. Falling over myself to accommodate the situation, I felt terrible in so many ways later on.”

Grossly Inappropriate

“Covered the whole toilet (seat, bowl, everything) in shit and came back to class with his hands still covered in poo – that was in a private tutoring school and all 10 students shared a bathroom. He was 16.”

“Had a girl who reached in her pants, pulled out her maxi pad and smushed it in another girl’s face.”

Watch as the Mamamia team confess to the strangest things their kids have done. Post continues after video.

Cruelty to Animals

“My senior year had a kid in our aquatic science class took a fish out of an aquarium (teacher had stepped out of room), using scissors cut off its fins (it was one of those really fancy goldfish) and set it on the counter and watched it die. Same kid threatened to rape the teacher. And had been caught on camera pouring flour into a tank.”

“Broke into his neighbours yard, stole his pet ferret, killed it, skinned it, pinned it to the door of the neighbours house….. more than once.”

“I used to teach two-year-olds at a daycare and there were three little baby wrens hopping around the playground and so another teacher and I pointed them out to the kids. The kids were all smiling and laughing, they loved them! Then one of the kids from my class, who was a little shit, got this big grin on his face and stomped on one until it was dead. It was horrifying. I scooped up the other baby birds and put them outside the gate (needless to say).”

Cruelty to Humans

"Lit a girl's hair on fire mid-lesson just to see what would happen. Thankfully it was noticed quickly and the girl was fine in the end."

"On his first day at our school (middle of the year transfer) he picked out who was essentially our alpha male 8th grader and proceeded to try to kick the living bejeezus out of him. For no reason. When he came back to school, I caught him trying to stab my classroom pet rabbit. Multiple times. Needless to say, he only lasted a couple of weeks before he was permanently expelled because of his violent tendencies."

Manipulative Minors

"Grade 2. Very manipulative. Threats to other children. The district psychologist comes in to observe. I tell the class that Mr. So-and-so wants to hang out with us for a period to see the cool things we're learning about. The student in question shows model behaviour all class. As soon as Mr. So-and-so leaves, said student winks at me and says, "How'd I do?""

"He loved making girls uncomfortable. He would get such a thrill out of it. He loved putting them in a position where they wanted to move away from him, but they couldn't (sitting on their desk, backing them into a corner, etc), but the thing is is that he was so fucking charming. He was LOVELY. He would say hello and goodbye to me and just smile. His smile was so unnerving. He came very close to putting a pencil in a girl's eye once, and was suspended for three weeks because of it. He said he wanted to see what would happen, and just smiled the entire time he was in the office with the headmaster. "

Sexually Inappropriate 

"Female science teacher here. I was about 2 weeks into my first job. Another student dropped a pen by accident, I picked it up. Straightened to find one of the biggest boys in the class (about 14 years old) standing right next to me. He got even closer and said "Good girl". I was kind of shocked, so just said "Excuse me?" and he replied with the creepiest ever top-to-toe survey of my body, a leer and then asked "Would you rather be a bad girl?""

The stories may seem extreme but a great deal of research has gone into picking up signs of criminality in youth.

Studies hope to understand how delinquent behaviours can be stopped before they become continuities in adulthood.

Feature image is a Banksy mural via Getty Images.