@a = 1 .. 5;

@b = \@a[ 0, 2, 4 ]; 
print "@b"; ## An array of references to aliases or copies?
SCALAR(0x18eece0) SCALAR(0x18eecf8) SCALAR(0x18eed10)

$$_ += 10 for @b;
print $$_ for @b;
11
13
15

print "@a"; 
11 2 13 4 15 ## It was mutated!