Step 1 :\(\left(x^{-5}\right)^{5} = x^{-5*5}\)
Step 2 :\(x^{-5*5} = x^{-25}\)
Step 3 :\(x^{-25} = \frac{1}{x^{25}}\)
Step 4 :\(\boxed{\frac{1}{x^{25}}}\)