Space Invaders

Ships from an alien source are approaching from the sky
Radio contact has been attempted but cannot be established
The instructions are to prepare for an attack by an unknown enemy
Light speed in three, two, one

Ravenous beasts
As far as the eye can see
A plague in the surface
A disgusting swarm in the skies
With a crush of thunder
A new demon appears
Unfortunately it's rotten wins
It let's out a petrifying scream

Final boss
Ping
It's time to fight back