The creature you're referring to is known as the Hydra in Greek mythology. Specifically, it is the Lernaean Hydra, a serpent-like monster that lived in the swamps of Lerna and had regenerative abilities, growing two heads for every one that was cut off. The Hydra was famously defeated by Heracles (Hercules) as one of his Twelve Labors.
Poseidon's pet is the Hydra, a seven headed beast (i believe) who grows two new heads with every head cut off.
The hydra of Lake Lerna (called the Lernean Hydra). Killing her was one of Heracles' labors.
Hydra was a nine-headed serpent that every time you cut off one of it's heads it grows two more in place of it's lost head. Hercules killed this monster by grabbing it's neck while cutting off it's nine heads.
A hydra was a many-headed mythological creature fought by Hercules. Every time a hydra’s head is cut off, two more grows in its place. Hercules finally defeated the creature by burning the stumps of the hydra’s neck, preventing it from regrowing.
It grows to adult as soon as you purchase the dragon amulet
It grows in level when you do.
It grows over time.
The Hydra is a nine headed Greek monster that grows two new heads every time one is chopped off. The only way it can be killed is if the necks are singed before the two new heads grow back. That is how Hercules killed it.
Earth and thunder. It looks lame at first, but it grows to look cool
Hair grows longer every day.
Everyone hair grows 1/2 inch every month but you can measure your hair every month and see if it grows
Aconites