The wasp that Blackarachnia uses for her experiment seems to be a gigantic specimen, considering that Blackarachnia herself is a giant robot. Compared to her, it should be by all means a lot smaller.
The animals that Blackarachnia faces at the end of the episode are also too big, making Blackarachnia look nearly human-sized next to them. The rat, in particular, seems extremely out-of-place, as it shouldn't be found in an African jungle-setting, and also appears to be much larger than any rat, but this can be forgiven, as it was meant to be a simple easter-egg. However there is no explanation as to why the animals are so large altogether.