(CW: death near the end. I don't know if this is necessary and it kinda gives something away, but hey—you don't know who is or how they are!")

Dib had come to determine that he only switched beings once he went to sleep—why Pilot got all weekend was probably because he didn't sleep. Madlad probably didn't even need it, he was so full of chaotic energy. Unfortunately, though, not the good kind.
He ended up skipping class the next day to go to the mall instead. Maybe he went to Hot Topic or snuck inside Spencer's, or went to the food court, or even the Pokéstore... no, actually. He robbed the watch repair place. He wasn't caught, he wasn't seen, he only took two things: both of which were watches (since, y'know, the store). Both of high price, both with jewels embedded into the sides. He just slipped them both into a pocket, and walked out. He didn't care if he was caught or if it was caught on camera; he'd just be gone by next morning.
He did the same in other places: a candy store, Hot Topic, this one place that sold cool gifts but had a defense knife selection in the back... pretty much anything he could quickly get in his pocket that could be of use or interest to him.

By the time skool let out, Dib had left the mall. ZiM was getting home from skool after a day of nothing, only to be met with the scar-covered Dib laying awake on his couch. "Dib!—"

"ZiM, this place smells awful. Have you even cleaned lately?" Dib's nose was all scrunched up.

ZiM at any normal time would protest or throw Dib out, but after the events of the day prior, he didn't dare. "Oh eh, uh... I've just not been in the best mood for that... y'know, ever since my Tallest..." ZiM trailed off, kinda just staring at the floor.

Dib had no Earthly idea what ZiM was talking about. He considered questioning it, but settled on thinking: ever since they what?
And that's when it hit him. It's not like it wasn't obvious, anyway.
"Ah! Right... I'm sorry, little ZiM—you don't deserve that one bit..." Dib sat up. "But! I got you a little somethin' that may cheer you up, hm?"

"Yes?" ZiM got a little closer and sat down, hoping for more cuddles.

Dib instead pulled out some candy pieces and one of the stolen watches. "Some sugar... aaand a time piece! Costs a lot—you could sell if you wanted to."

ZiM removed his contacts and wig, looking down at the items in Dib's rough hands. "Oh... eh, thank you..." he sighs, leaning back.

"Hmm... dear bug doesn't seem too happy about anything today..." suddenly, a second idea came to him—it rather annoyed him, making his anger slowly rise like heat. "If you were abandoned here on this rock with no authority... does that mean you have no interest in preparing the Earth for their arrival?" His voice was shaking, it was on the brink of raising... he resisted, trying not to scare the alien. Right now.

"I... I guess not..." ZiM sighed, leaning back against Dib.

Dib, however, pushed him away almost immediately upon contact. "Not? You guess? Oh, so you just have absolutely no authority to prepare Earth for... no one taller than you?" He growled. "Great. Now how are you going to be able to repay me if I can't even help you?!"

"But you brought me some parts I needed to build a—"

Dib threw up his hands. "Yes, I know, but that was never finished! I just want to help you, ZiM! With literally anything..." Dib grabbed a piece of his hair, just... growling more. His shoulders tensed, his knees came up to his stomach, and his hair was a placeholder for ZiM—he wanted to just grab ZiM and scream at him, but he didn't... he couldn't.

ZiM noticed Dib's exasperation, and shrunk down a bit. "Well... you helped last night with making me feel better..."

Dib un-tensed just slightly, slowly looking over at ZiM. "I did... I did!" He uncurled from himself, grabbing ZiM—like, hug grabbing. "You're still not feeling too great, correct?"

"I mean... I was able to go to skool today." ZiM felt Dib tense. "B-but... this still isn't a great feeling..."

Dib leaned back against the couch, just... holding ZiM. His hold was a bit tight, but ZiM didn't mind—he was just happy for more holds. "Anything interesting happen today?" One of Dib's hands pet an antenna.

"Not... really?" ZiM sighed. "Didn't see you in the halls or at lunch, so no exchanging of looks. Someone threw a potato at me; might've been Keef, he's been more annoying than usual recently..."

"He has?" Dib huffed. "Yeah, he threw a ball at my head the other day. A bit of an asshole, huh.."

"I don't... know what that mean."

"I had my own annoyances today! Someone almost kicked me out of a store just because I knocked into them while holding something!" He began to recall when he made an attempt to knock out a mall worker. "Such annoyances..."

"You get so much grossness every day; how have you not done anything about it?"

"Hm?"

"I mean... only after a few days of insults when I first got here, I tried to kill the whole class. How have you not done something like that?"

Dib stopped petting ZiM, and thought. For a long time. Rusted, sharp gears were turning in his head, and what was working wasn't anything good. No, not at all. "Oh, oh, sweet, little Irken..." he held ZiM a bit tighter. "You've just given me a gorgeous image..."

ZiM smiled a little—he wasn't sure what he'd done, but it seemed to make Dib happy.

"Hey... you really have no more higher-ups? No one taller than you?"

"...not really... It doesn't really give me anything to do. I don't know what my current purpose is..." ZiM's antennae began to shake, just slightly.

"Wellll..." he started to pet one again. "...you know... there's someone in this room who's very tall... knows his way around the planet... who can be of good authority..."

ZiM's free antennae raised. "Are you implying the Dib should become ZiM's new Tallest..?"

"Oh, no! Not me entirely..." he grinned. "Juuuust when I look like this. C'mon, ZiM... I'm here to help. You need an authority figure! You see that yourself, don't you?"

ZiM stayed silent for a bit, and his antenna lowered. "...I do."

"Perfect!" Dib closed his eyes, exhaling all his air. "Remember... even if I am your higher-up, I'm still a friend to you!"

ZiM closed his eyes a bit. He wasn't quite sure what just happened, but... he wasn't fighting it.

Dib left ZiM an hour or two later, taking that same walk path from Saturday. He was looking for someone...
...and, eventually, found him. The stupid orange hair... the boring blue shirt. Definitely him. Seeing him made his blood nearly boil, and his head go cold. Why didn't he just stay exploded? He didn't want to see him any longer... unfortunately, he had to.
Dib approached. "Hellooo..!" He gave the fakest friendly grin possible.

"Oh, hi..?" Keef turned around, waving a big awkwardly. "I'm sorry, you look familiar...do I know you?"

Dib was a bit confused—obviously it was Dib! He, for just a second, looked at the reflection of himself in the window of a nearby store. That's when he realized. The scars, the tattered clothes, the paler skin tone, the darker hair and different haircut, the... possible different eye color...

Pilot was almost an entirely new person.

"Oh! Well, yes, I'm sure you know me... from skool! We have lunch at the same time." Dib laughs a bit, shifting his weight. "Anyway... I have something I need to show you! Will you follow me forrrr... just a second?"

"Uh... sure!" He shrugged and followed Dib, who walked around to behind the store.

Dib's hands were shoved deep in his pockets, looking through each of his stolen items. He felt around, searching; candy wrappers... a necklace... there. He felt a long, thing piece of metal and felt it down, gripping the smooth, not as cold part.

"Sooo... what was it? I kinda have something after this, so I don't really have all day..." Keef looked behind himself, huffing.

"Oh... I'm sure they can wait for you just a little longer..." Dib, before Keef could turn back around, plunged the stolen knife into Keef's neck. The other boy froze, eyes widening. A crimson color began to show, the faint smell of copper getting closer to Dib. He removed the weapon, only to shove it back into the boy's chest. To remove it, he just kicked the body down.

Keef was dead.

Now, if these were normal circumstances, Dib wouldn't know how to feel. On the one hand, he's always dreamed at getting back at people, but... not like this. Dib wouldn't feel good at all.

Unfortunately, this wasn't normal circumstances.

Dib stood up tall, staring down at him. "...pathetic." He grinned, leaning up against the wall and kind of just watched for a good couple minutes. Once he was satisfied enough, he turned and his walked out into the street.
He felt amazing. There was a sense of pride in his chest, and it felt like an enormous weight had just been lifted off his shoulders—he finally felt like he truly existed. He was doing something! He was laughing, laughing for himself, at everyone, and everything. Like the mall, like Keef not recognizing him, no one would know it was him. No one could know! The only one to recognize him was ZiM!
He doesn't look like Ghost at all—well, he looks like he could be a distant cousin... but! Still, not him. Pilot could do whatever the hell he wanted, and just go to sleep. Repeat. No one, not even Ghost, would know he was stealing, or killing, or anything. He had no more fears, almost. It was perfect...

Ghost was his perfect hiding place.

His singular fear was Ghost finding out how to get rid of him.