Δ Milotic b

It's been 300 long years since the generation ship Arceus left their home planet, carrying roughly ten million human lives and a massive bank of pokemon with it on its journey to find a new home for the remains of humanity. Following a handful of failed attempts at planetary colonization in the first century, most denizens of the massive ship had long given up on ever setting foot on solid ground - that is, until their survey satellites detected Δ Milotic b on their long-range scanners. Smack dab in the inhabitable zone of its native solar system, this newly discovered planet appears perfect when the first unmanned scouting probes investigate: it appears to have an atmosphere that would support human life without any extensive preliminary terraforming, as well as what appears to be a thriving ecosystem of its own. Compared to the hastily built and even more hastily abandoned colonies on "dry" planets they've tried before, this discovery seems like a godsend to the spacefaring Arcians. After three centuries of wandering, humanity might have finally found their lucky break.   There's just one hitch: Δ Milotic b is already inhabited.