Two options:
1, Aliens are amongst us, and we can only see them when we're stoned off our tits.
2, Both had been exposed to similar stimuli, and one was in a suggestible mood after the other said they saw aliens.
Hmmm, now which is more likely?
what similar stimuli? how similar? and whether either one of them were in a suggestible mood is entirely speculative. i've been pretty high and i've never seen aliens. there are also people who claim to have seen aliens while sober.