In nature, size sometimes do not matter. It's all about your strategy (bite location, poison etc). In the case of ground beetles, it takes bite location, sheer cussedness to hang on to a wildly bucking prey and poison to fell the stronger and bigger toad.
Don't click on video if you do not want to see nature red in tooth and claw. As in live consumption of prey by said beetle. You have been warned.
Ah, Toad. R.I.P.
Courtesy of New Scientist.