Beetle Drones crawl on land like actual insects but when they are in battle mode, they stand up on two legs. They could travel in great speed on both land and air. They were armed with four powerful scythes attached to their body. Though effective machines, they were no match for the skills of Samurai Jack. However, in sufficient numbers, they can and have proven dangerous to even Jack. Later they were upgraded with insect-like wings on their back which allowed them to fly.
In their first major appearance, Jack had recently arrived to the future and managed to destroy the drones sent by Aku after formulating a plan to protect the canine archaeologists. After this battle, the Beetle Drones made minor appearances throughout the rest of the series.
Though they are robots, they seem to be able to possess a sense of fear, which can be seen when at least one beetle drone attempted to retreat during a battle against Samurai jack, and later, around 50 years into the future when a number of damaged battle drones were seen retreating from three archers.
In Season 5, their appearances have changed quite a bit. They have now been upgraded to resemble stag beetles as opposed to rhinoceros beetles the previous models were based on. Their eyes are also now red and they no longer have a toothy mouth on their faces. They also come equipped with large pincers and also appear to be slightly more resilient in battle than the previous models, proven by the fact that some beetle drones were still functional even after being hit by multiple arrows, one beetle drone even remained functional despite losing much of its lower body and legs after a battle with some archers. In the second episode of the fifth season, Aku's scientists also bring forth "the most epic version of the beetle drone yet", an enormous drone model upgraded beyond any of its predecessors.
Despite their change and upgrade, they are still a fodder to Jack as always.
They were presumably erased from existence after the past Aku's destruction since Aku was not there to order evil scientists to create them.