BioShock Hints

In order to do this, you need the Hypnotize Big Daddy Plasmid and the Natural Camouflage Tonic. All you have to do is use the Hypnotize Big Daddy Plasmid on a Big Daddy so that he thinks you're a Little Sister and protects you. Now here's the fun part - simply find and attack another Big Daddy and your Big Daddy will attack it to protect you.