To find $f(-6)$ for the function $f(x) = -x^2 - 2x - 1$, substitute $-6$ for $x$:

$f(-6) = -(-6)^2 - 2(-6) - 1$ $= -36 + 12 - 1$ $= -36 + 12 - 1 = -25$

Thus, $f(-6) = -25$.

Would you like more details or have any questions? Here are some related questions you might consider:

1. What is the vertex of the quadratic function?
2. How do you find the x-intercepts of $f(x)$?
3. What is the maximum or minimum value of the function?
4. Can you graph the function $f(x)$?
5. How would you solve $f(x) = 0$?

Tip: Quadratic functions can be analyzed using their standard form, vertex form, or factored form for different insights.