Without Number

The Tyranid creedo is "Without Number", meaning that they have limitless numbers of creatures with which to use against their foes, all the more to consume them and assimilate them into their Hive fleet. They are much like Orks, similar only to the fact they spawn at alarming rates. If you think this isn't much, imagine the sky being blacked out by thousands upon thousands of gargoyles that fly in the air to swarm their foes.

I shudder to think of how I'd die if they'd arrive on Earth.