Ink Sac

Ink sacs are the darkest primary color dye.

Squids
Squids drop 1–3 ink sacs upon death.

Fishing
Ink sacs can be obtained as a “junk” item from fishing.

Compound creation
Ink sacs can be created from its base elements, using the compound creator.

ID
In bedrock edition ink sacs have the ID name  with data value 0.

Trivia

 * In the statistics menu, the item name “Ink Sac” does not appear when the cursor is hovered over its image in the statistics page. This is due to it referring to all dyes combined.