From the brushes palette, drag the ink drop brush to your document page and drop it. Select the items and change their colors and transparency to get a black one, there is also a blue grey swatch color you can click on and change to black for the little splat on the top right.
Once you have changed the elemtns to beck select them all (including the box set to fill of none) and drag this back to the brush palette. Save this as a scatter brush and name it (eg: ink Drop 2). You will then want to enter the settings for size, spacing, scatter, rotation from the original.