This happen to me during a fight seen in the desert by cactaur island. It was the shitz!!:p

I think it's the alien you get to fight after you spot him in his ship three times. You have done it the first time i think the second time you see him is near balamb garden. The third time i have forgetten so you should wait until someone else posts.

When you have spotted him three times you fight him. But he is a total push over. He will ask for a elixer (sp?) in return for his card. But if you can't be bothered just go ahead and kick the little blue buggers a$$. *lol*

So as i said i can't remember all of it so i would go by my explanation.

aeo

<font color="4422BB"> you have to find his ship un occupied near the ICTH and destroy it (it has demi draw magic :D) before u can encounter the alien guy.</font>

no no no
you see him 4 times once:
in the desert
on the beach just east of timber
on a small island east of tribia garden
and the other
south west of winhill

each time they carry somthing different
i.e. a cow or a sculpture depending on its whereabouts
then u can fight the ufo on top of the mountians near the chocobos holy ground when u beat him u get a pupu card (or alien card)
if i remember correctly

it is much easier to spot the ufo's if you have enc-none junctioned

I fought him once you see him at different locations, When you actully get a chance to fight it only destroy his ship. Then a little alien comes out and I think it asks for an elixer then it gives you the Pupu card which should fill a gap in your card colection.

<font color=red face="comic sans ms">Ok, the UFO can be found at the 4 locations that Ozma mentioned, then you actually fight it in the area to the north of the Esthar continent (Grandidi Forest, although it's in the small area that isn't actually covered by forest). Once you have fought the UFO, the alien will escape.

The alien can be found in the area where Balamb Garden used to be. It will ask you to give it Elixirs; you have to give it 4 in total to help it, and you will get the PuPu card (rare) in return. If you decide to kill it instead (it only has 10HP), it will drop an Accelerator which teaches a GF the Auto-Haste ability. Or you can Devour it to get a +1 bonus to your speed stat, however this is not really worth it. If you are going for a complete card collection then help it, as this is the only oppurtunity you will have in the game to get the PuPu card. :)