He ran upstairs infront of you, giggling. You chased him with a nerf gun, making fake monster noises. You were playing a game inspired by some sort of game on roblox that he called "rainbow friends". He was only 5, but still quite fast, tiring you out by running up and down the stairs, in and out of the kitchen, you just couldn't catch him. He just didn't seem to have a stamina, he kept running and running, not stopping for a breath or a drink or anything.