Instead of feeding it when you have the bug repellent, Gilly suit and cactus soup all in your bloodstream… why not take a couple of billboards and trap the mantis..

I was able to do it using just two billboards.. the mantis body is very long.. so I use one billboard to block it from moving forward and the other one was put down right on top of its middle section…. It was trapped….

I left the area and it glitched out of the trap…

I was able to do it again though. So billboards are really convenient for the mantis provided that you have the Gilly suit and the bug repellent and the cactus soup in play.