100% Xatu

Don't invest anything and leave it as it is. Xatu isn't really useful in current game meta. Base stats is not good enough.

100% is always a trophy. So congrats on getting this and maybe a future reroll will make it useful. But for now, the battle part of the game is really irrelevant.

Well if you have plenty of fast TMs, it is not that big a cost to switch to its best moveset. As for stardust though, you are probably much better off powering up Lugia.

It does have the same base attack stat as Lugia,lol

No. I caught a level 27 wild 100% Natu and evolved it. That's it. Even when it's so close to 30, I won't bother with this pokemon. It has no use. It's just a trophy

Nah. It's just a trophy. Useless pokemon are useless pokemon regardless of IV's.

I was going to say "I for sure wouldn't max it, but if it's a modest investment (say lv 28), then I'd push it to 30 and absolutely no higher." but then I looked at my list of things that I'd like to power up to Lv 30; Lv 27 96% AS/O charizard, Lv29 98% C/P Slowbro, Lv20 AT 100% Vape, and they are soooooo far down the list (thanks legendaries) of priorities, that a 100% IV Xatu wouldn't even crack the list.

I have a 100% Xatu too. With Air Slash and Future Sight. But is useless lol