Alien Life Could Already Be Here!

I have always thought that fungus was very alien to this world. I realize that it has been here practically forever. It gets into everything and does not actually fall into any of the other flora or fauna categories. It has been shown that fungus actually has been trying and succeeding in establishing a symbiotic relationship with plants. Actually most plants have specific types of fungus that help them absorb nutrients from the soil, in exchange for carbohydrates.
It has been speculated that fungus may actually be attempting to establish a symbiotic relationship within the animal kingdom.
back to the point. I can definitely imagine spores as planet hopping.