Purple
"I'll kill him!" I hear Sunstreaker roar through the base. There's load, pounding footsteps as he comes closer. I wonder briefly what could have made him this mad, but then he enters the room I'm in, and I immediately understand. I clap my hand over my mouth and look away, hoping he doesn't see my shoulders shaking from my repressed laughs. Oh, my god, he's purple! Completely purple, and sparkly at that! No wonder he's in a murderous rage.
"Where the fuck is he?" Sunstreaker shouts, and suddenly Sideswipe is next to him, trying to calm him down. Even his twin can't calm his temper this time, though, and Sunstreaker storms off again. Sides looks around helplessly, eyeing Bumblebee and I with a pleading look before rushing off after his brother. 'Bee looks at me and I nod, letting him lift me to his shoulder and hanging on tightly.
"Damn you, Ratchet!" Sunstreaker yells, and that answers my question of who did this to him. That's just cruel of Ratchet, even if the twins are constantly pranking him. Everyone knows the Sunstreaker is obsessed with his looks, and that if you even come close to scratching his paint job he glares at you for a week. Making him like this is just asking for a death sentence! There's a massive crash and the sound of creaking metal. Bumblebee makes a quick dash for the training room, where it apparently came from.
"If you do kill me, you'll never find out how to get that paint off of yourself," Ratchet says calmly from his position under a very pissed off Sunstreaker.
"How do you know I won't just kill you after you change it back?" Sunstreaker growls, and I think he makes a good point. Did Ratchet really think this through?
"I'll make you swear on… Sideswipe's spark that you won't before I change you back. Do you swear?" Ratchet asks, answering my unasked question. He really is stealthy. I hope I never get on his bad side. Sides gapes and Sunstreaker looks like he's going through an internal battle. Kill Ratchet or save Sides. During the pause, even Ratchet looks a little unsure of his plan. After a tense minute, Sunstreaker shoves Ratchet away harshly and stands stiffly, holding himself back.
"I swear on Sideswipe's spark that I won't kill you… for this new paintjob. I make no promises for the future," Sunstreaker announces. Ratchet nods in agreement, not even questioning that Sunstreaker might kill him one day. Together, with Sides as a type of guard and referee, they make their way to the med lab. Oh, so that's how Ratchet colored him in the first place! Sunstreaker was injured pretty badly recently, and I guess he must have been the Autobot equivalent of unconscious.
That must have been when Ratchet got to him. Of course, I'm sure Ratchet patched him up beforehand. Ratchet might have a devilish side, as shown here, but he wouldn't risk Sunstreaker spark for a prank. Just then there's a large thud from the direction of the med lab, and a moment later Sunny and Sides run out laughing, Sunny apparently over what happened in light of the new prank.
'Bee and I make our way over to look, and see Ratchet lying flat on the ground, unmoving. 'Bee crouches down to get a better look, and Ratchet glares at us, his facial features seemingly the only things working. "They disabled my motor functions. Get them back online so I can go murder the twins!" Ratchet yells, and we all hear an increase in the laughter right outside.