Find the exact value of $\cos \left(\cos ^{-1}(-2)\right)$. Write your answer in radians in terms of $\pi$. If necessary, click on "Undefined."

Step 1 ：The cosine function only takes values between -1 and 1.

Step 2 ：Therefore, the inverse cosine function, or arccosine, is undefined for values less than -1 or greater than 1.

Step 3 ：Since -2 is less than -1, \(\cos^{-1}(-2)\) is undefined.

Step 4 ：Therefore, \(\cos(\cos^{-1}(-2))\) is also undefined.

Step 5 ：\(\boxed{\text{Undefined}}\)