Clay referred to them as the "Toxic Swarm."
These creatures were communal life forms, in a constant state of death and division, much like human cells, metabolizing at an exceptionally high rate.
Therefore, Levi needed to consistently feed them large amounts of toxins or flesh to ensure the vitality of the Toxic Swarm.
Otherwise, without a continuous source of energy, these undead beings would eventually wither away.
Although they were a low-quality version of the Totem Insect, it had to be admitted that Levi was quite impressed by the power of this Toxic Swarm.
After parasitizing a host, the Toxic Swarm could give birth to a venomous body impervious to blades and spears. It could transform into a terrifying poisonous cloud that devoured everything. Moreover, it could induce the host to undergo a splitting rebirth. However, each regeneration required a substantial amount of energy.
