Enterprise2001

[Dr. Phlox takes a ball of hair out of a small cage]

Ensign Hoshi Sato:
What is that?

Dr. Phlox:
It won't bite. It's called a tribble.

[he hands the tribble to Hoshi]

Dr. Phlox:
It was extremely difficult to acquire. They're outlawed on most worlds.

Ensign Hoshi Sato:
Why? Is it dangerous?

Dr. Phlox:
Oh, far from it. All it's capable of doing, really, is eating and breeding. The problem is, they breed quite prodigiously.

[Phlox takes the tribble and feeds it to one of his other creatures]

Dr. Phlox:
The only thing that keeps their population in check is the abundance of reptiles on their homeworld.