Do you mean they come from outer space?
Why not?
How many worlds are there in the universe?
Millions, perhaps billions
True, they're millions of light years away
But perhaps a form of life like this doesn't have the same concept of time as we do

It stays inactive, passive
As long as it's in the absolute freezing temperature of sidereal space
Then, once it falls into an atmosphere like ours
The seeds germinate and the eggs grow

If you're talking about cells wandering in infinity
They have one chance in several billion of falling on our planet
That's practically impossible, unless
Unless they come from much closer, but

Of course
Of course, try to imagine
Of course, try to, of course, of course, of course, of course
Of course, try to, of course, of course, of course, of course