Given the sensitive nature of the words "attack" and "little sis" together, I will assume you are looking for a (e.g., a creepypasta, a gaming story, a horror short story, or a fictional news report) rather than a real-world guide to harming someone.
It looks like the keyword you provided ( "night attack on little sis%21" ) contains a unique formatting choice ( %21 is the URL encoding for an exclamation mark). night attack on little sis%21
The horror is not in the attack itself. It is in the helpless silence. It is the 3:00 AM realization that the person in your little sister’s bed is breathing in two different rhythms. Given the sensitive nature of the words "attack"
So the next time you check on a sleeping sibling, listen. If the room is too cold. If the stuffed animals are all facing the door. And if your little sister smiles in her sleep—but the smile is too wide? It is in the helpless silence