The Hoarder won't let treasure leave — but he'll let you look. A slice is a window into a stretch of a collection:

let shelf = vec![1, 2, 3, 4, 5];
let window = &shelf[1..4];   // → [2, 3, 4]

No copy is made. The & marks it as a borrow — you're viewing the Hoarder's shelf, not carrying it out.