Wow, I looked away for a second and when I looked back, the image looked like it was twice as big as it was before. I was having a hard time tying to keep myself from laughing, that did me in. Staring at it for a long time didn't help either.
But, Does Tenshi know that Kogasa actually doesnt hit people? Or is she just doing it for the thrill of it? Or maybe just because shes bored? This is such a random pairing with no context to the picture at all. But mega cute as per this artist's usual stuff.
Eh... she's often depicted as being tormented by Sanae (when they don't have the opposite happening that is), as well as just general misfortune when she tries to sneak up on people to scare them.