There’s a glitch that lets you get ink-sacks in minecraft pe 0.7.2/0.7.3 to get this to work you will need (if in survival) an arrow,bow and bonemeal (if your in creative) only a bow and bonemeal is needed.
Step 1: Make your bow like mine and then shot the bow.
Step 2: As soon as the arrow leaves the bow QUICKLY click the bonemeal.
Step 3: If this didn’t work try again because it will work just depend how fast you click (my friends can get it their first time I get it like my 8th)
Step 4: Admire your useless item 🙂