Peter, crawling to the kitchen of the compound at 3 AM: WHERE is the appley juice
Sam, hitting him with a broom: WHAT *smack* THE *smack* FUCK *smack smack smack*
How the other avengers would react:
Bucky: same as Sam but “WHAT * THE* HELL”
Tony: screams and drops whatever he is holding. The first time. He quickly gets used to it.
Steve: his heart stops beating for a second and it is several more seconds before he remembers to breathe. He will never fully understand this kid.
Natasha: IF he manages to startle her, very nearly shoots him and then lectures him about sneaking around in a house full of armed and traumatized soldiers/spies/scientists.
Bruce: about jumps out of his skin and then laughs for an hour.
Thor: joins the quest for appley juice.
There are many reasons Clint doesn’t live with these people.
Honestly, it is less creepy when he’s on the ceiling…