I don't think your monster has grown so large yet.
The monsters themselves grew old and lay down and died.
And when they are obeyed, the monster grows hungrier.
No doubt those forty-carat monsters didn't grow on bushes even in Gaikon.
"This happened over and over until finally the monster grew depressed, gave up, and turned into a mountain."
When it exploded, a vent of steam would make the monster grow.
The monsters of the ocean grew larger than those of the lakes!
It was a child asking someone to explain why the monster under the bed has grown a new and scarier head.
The red monster would grow if fed, though Pasgen was still trying to discover a way to destroy it.
If this monster grows stronger, it turns the victims (including Amy) into plants.