Yeah Its better to be a skeptic, but still why a mantis? Why so many different stories about the same creature that is alien/insect looking 
Check this one:
"Mantis' power
Hey there!
Hey there! This is my first trip on Psilocybe. I've found only a big one close to my grandfa's lil farm.
I ate him about 9:30 pm, with empty stomach. Then, i felt like vomiting, so i smoked some ganja (you know, anti-emetic stuff). Then i went out of the house, there was a sky FULL of stars. There was cold like hell! Almost freezeing! But i stand there, smoking and waiting. Then, everything just frost, as if what i was seeing was just an image and the real world could be different. Then, a truck passed by the sand road in front of the farm. I saw a truck, pulling a lot of wagons with wood, and i thought it was some kilometers of wagons, then, when he was climbing the hill up, away, i saw, it was just a normal truck, with no wagons! Weird!
Then, i began listening to all the sounds of night in the 'jungle'. I could hear just everything. That was a dark night, but i could even see more than a dog, wich was playing with a black cat, he couldn't see the cat, but i could. I also talked to them, and a weird animal (i think it was an ally) came to us. It was like a catdog, or a dogcat. White, i never seen it. The other animals stopped playing around and talked to he. I got scared, but i talked with he too.
Then, it was tooo cold and late, i had to get in. My body was really tired, but my mind has never been running so fast! WHen i went to bed and tried to sleep, i was seing lots of colors of closed eyes. Then it happened to me: i began morphing phisically! I've acquired a deformed form at first, square head and face. Then i transformed myself into an alien, almost like Alien of the movie. Then, finally i went into the best of all forms: the Mantis form. It was really wonderful to be a mantis! Lucky me it was dark and i was in my bed, imagine if someone around see a 1,75m tall green mantis just walking around!
By words, we cant tell a experience, no trip report can describe a trip in its richness. That's why im kinda against these stuff of trip reports, but anyway...!"
Why mantis? I mean, I don't know. One person starts to discuss it, then all of a sudden everyone who has a trip starts to see mantis.
Its equivalent to alien abductions. People only started to report little green aliens with weird shaped heads when the movies started to depict aliens in that form. And most people who have a supposed alien abduction all re-tell relatively the same stories.
