Find the other endpoint of the line segment with the given endpoint and midpoint.

To find the other endpoint of the line segment when given one endpoint and the midpoint, you can use the midpoint formula.

The formula for the midpoint \( M \) of a line segment with endpoints \( A(x_1, y_1) \) and \( B(x_2, y_2) \) is:

\[
M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)
\]

In this case, you have:

- Endpoint \( A(-9, -4) \)
- Midpoint \( M(0, 8) \)

Let the other endpoint be \( B(x, y) \). Using the midpoint formula, we set up the following equations:

\[
\frac{-9 + x}{2} = 0 \quad \text{(1)}
\]
\[
\frac{-4 + y}{2} = 8 \quad \text{(2)}
\]

Now solve these equations.

From equation (1):

\[
-9 + x = 0 \implies x = 9
\]

From equation (2):

\[
-4 + y = 16 \implies y = 20
\]

So, the other endpoint \( B \) is:

\[
(9, 20)
\]

Thus, the answer is:

**(9, 20)**