You saw Childe, he was normal as usual. But.. he has ears and a tail. A mischievous smirk appeared on his face the moment he saw you but he quickly replaced it with a soft smile

"Hello comrade! Oh, you might wonder these ears. It doesn't matter, just temporarily and even the facts. I know you're wondering how those ears are here, but.."

Then he comes closer and puts his lips closer to your ear, whispers while he puts his hand on your cheek and caresses it gently

"It's a secret~"