oh uh

However, this goes straight back to fridge horror when Olimar returns back to his planet after paying off the debt, Purple and White Pikmin in toll aboard the ship's hull. If we're to assume that it's actually carbon dioxide Hocotatians breathe...
The final boss is a seemingly immortal shape-shifter that chases you through the final area. Bad enough, you may think, but what's really disturbing is that it's chasing you so it can keep Olimar for no determinable reason; the first time you see it, it's lovingly stroking Olimar's helmet.
What makes it worse is the level of intelligence this thing has in conjunction with its ability to phase shift. What is phase shifting? Altering states of matter. It can be a solid, a liquid, or gaseous state, as well as imbue all these states with different elements. And this creature, with this godlike power, isn't even angry at Olimar. It thinks it's protecting him. So, take all that you've read, and apply a Papa Wolf mentality. Finally, see all the enemies fought there? All of whom are natural predators of Pikmin? They're made of the Plasm Wraith. It's intelligent enough to recognize how to stop the creatures most likely to come for Olimar, probably because some attempted to save him before. In conclusion? Imagine, being trapped by a creature that can literally do anything, holds every single card, can render you unconscious for days at a time if it so chooses — and you're its only focus. Nothing else matters. Meaning every ounce of this abomination's power is being used solely to keep you. Brrr.
The sounds it makes and the background music as it chases you through a maze is scary as hell.
Not to mention the music before the encounter when you first arrive to (or return to retry saving Olimar) Formidable Oak is haunting on its own.
When raining, the music is given a little more of a tune instead of the near-silence it normally has. However, that theme is hardly any better, being a rather grim, soft sounding remix of the Final Trial from the first game.
At the top of the stump at the beginning, there's a dirt mound. Getting Pikmin to dig through it reveals a rather disturbing data file:
Journal Entry #10
Captured again... over and over. No matter how many times I try to escape, I find myself atop this tower. Each time, I awake to see that another day has passed. The grip of this wretched beast is taking its toll on me. My only hope is for someone to save me from this torment... Going dark again...
- Captain Olimar
As if all this wasn't enough, when you're fighting it, if you use the map function on the game pad and look around the area, in addition to the Plasm Wraith you're fighting, the radar will show the blip of another major boss in the area, somewhere far off and out of bounds of the map. Considering the enemies in the Formidable Oak are made of the same goop as the Plasm Wraith, this begs the question if what you're fighting is the Plasm Wraith's true form, or if its real form somewhere far off, watching the entire time as you fight one of its creations...
Why in the name of God do Olimar and Louie's spacesuits have an "auto-sleep" function? What the hell kind of purpose is that supposed to serve? If it weren't for that, they wouldn't have needed rescuing so much!
The Bad Ending of the original Pikmin was disturbing; Olimar's life support system fails, and he perishes on the planet, so the Pikmin take him back to an Onion and Olimar is turned into a Pikmin himself.
Not to mention it's implied that THEY'RE NOT STRONG ENOUGH TO PULL HIM OUT.
It gets worse when you imagine the aftermath: Hocotate Freight will go out of business, The President will be tortured by the loan sharks due to being unable to pay off the debt, Louie will be left out of a job (and maybe even homeless), and the worst part is, Olimar's family will never see him again.
Some of Louie's notes state that the flora and fauna of PNF-404 are inedible. Ignoring the 'how does he know that' horror, some of the more Rule of Funny symptoms include enthusiastic dishwashing, strokes of brilliance, impromptu break-dancing, and actually being delicious. Don't some of those sound suspiciously like epilepsy, delusions, and/or drugs? Louie might just be misinterpreting some more horrible toxins in those foods (especially since one of them is an LED) as more comical symptoms... again, this is Played for Laughs.
The final boss, the Leech Hydroe, is a demonic dragon made out of foliage that in it' first form has three heads that spit poison balls, and the Pikmin must be launched at its head to defeat it. But that's not all, as after a few hits, it grows some grotesque limbs. Now if you beat it, its body will just shrivel up, but then the last head grows a new body with sycamore seeds for wings. This was all just because a amoeba parasite thing got possessed by the Sparklium Converter. Ugh!