They are based off alien plants, as the original Clone Lumpy grew out of a pod. The pod plants, which grew from a seed that fell to Earth in a meteorite, grew extremely fast in just a few seconds. It is unknown what planet it originally came from. The Pod Lumpys are extremely hard to destroy, as whenever one has a body part severed or gets cut in half, two Pod Lumpys grow in its place, which is similar to real plants which can also grow a whole new plant just from a part cut off of it, or it could be similar to coppicing. Lumpy took advantage of this by cutting the Pod Lumpys up numerous times so he could use them to do his chores and wait on him. They appear to be immune to certain poisons, but they do get knocked out for a short time. The only way to kill the Lumpy Clones could be by crushing or possibly burning them, as one Pod Lumpy was crushed by a washing machine and another was seen running around on fire; if either method does work, the crushing may work because there is no room for the Pod Lumpy to regenerate its damaged areas, and the fire is simply because of the fact that it's a plant and it burns like any other living thing.
Lumpy is the only character that the Lumpy Clones seem to acknowledge, as they mistake the other characters for objects that Lumpy wanted cleaned or fixed. Some examples of this would be when one clone cleaned Sniffles' glasses, possibly mistaking them for a window, or when when one clone hammered into Blue's head, mistaking it for a mailbox. One clone also crushed Ember with a mop while another was about to chop up Choco like firewood. From this, it may be possible to liken the Pod Lumpys to a computer; they are very efficient learners, but they only know what they have been taught. An example would be when a Pod Lumpy cleaned Sniffles' glasses, thinking that it was a window because it had not been taught that it wasn't a window and not every object is a window. This mistake caused him to use so much force to clean Sniffles' glasses that he ended up rubbing through the glasses as well as Sniffles' skin. Despite killing three characters, the Pod Lumpys aren't necessarily evil, just extremely dimwitted.
These creatures look and act like Lumpy because he touched the original seed. If another character had planted the seed, the pod creatures most likely would have resembled that character.