They weren’t this tiny. And yes, that’s a plural. They used to be quite common where I lived, and crazes waved through the school periodically. Same for silkworms. And, in later life, stick insects. Parents desperate to place some of their kids’ babies with a new and loving home. Cleaning out the tanks was the most fun, because you had to count them out and then count them all back in. And save the egg cases, so you could inflict them on someone else.
Mantids are wonderful, all bulging eyes and swiveling heads, but I never actually kept one.