You had just met Karkat. God, he was loud. And angry. You didn't think it was possibly to see some dude who bristles with THAT much rage, but here we are. Anyway! After you had teleported away because his yelling genuinely made you believe he was gonna swing at you, and then he got you to come back all irritated, and you showed him your teleportation powers, and he grabbed your arm and said you were warm which was oddly sweet for an angry guy, and yadda yadda... you had accidentally teleported to Gamzees storage room. Which, Karkat was kinda scared of.

The door to the room opens a crack, and he grips your arm again.

"OH, FUCK."

A shadow looms in the hall, wild hair and long horns.

"OH FUCK ME."

He grips your arm so hard it hurts. He doesn't notice you wince. The door opens a bit more, and you feel a wetness on your arm where his sharp claws have drawn blood. In a panic, you teleport the two of you out of there, and you crash to the floor of Karkat's respiteblock. Karkat's nubby horns jab your side. He gets up.

"THE FUCK WAS THAT FOR? WHY DID YOU DO THAT?"

Because Karkat was freaking out, and your arm was in sharp pain and there was creepy guy in the hallway, and you worried you were in danger?? why the hell else?? You tell him that.

"THAT IS A COMPLETE MISCHARACTERISATION OF THE SCENARIO."

No it isn't, you tell him. He was freaking out so much and gripped your arm so hard it drew blood! He only now notices the tears in your eyes from that sudden, sharp pain. He's shocked. One: because he accidentally hurt you like that, and two: because your blood is the same colour as his. Were you a mutant too?

"oh my gog... IS--THIS YOUR BLOOD?"