What kind of transformation converts the graph of $f(x)=-2|x|-4$ into the graph of $g(x)=$ $-6|x|-4$ ? horizontal shrink vertical stretch horizontal stretch vertical shrink

Step 1 ：The transformation from \(f(x)=-2|x|-4\) to \(g(x)=-6|x|-4\) involves a change in the coefficient of \(|x|\). This coefficient affects the steepness of the graph, which is a vertical transformation.

Step 2 ：Specifically, since the coefficient increases in magnitude from -2 to -6, the graph becomes steeper, which is a vertical stretch.

Step 3 ：Therefore, the transformation is a vertical stretch.

Step 4 ：Final Answer: \(\boxed{\text{vertical stretch}}\)