Negative damping in simulink simscape

I want to realize a negative damping system.

My idea is to use the Variable Translational Damper, however, it doesn't support negtive coeffcient. Its parameter of damping coefficient must be bigger/equal than 0. I tried to switch the R and C connection, intuitively, the damping force would be negative. However, in both cases, the damper still damp the mass vibration as the output figure show.

Are there any other way for a negative damper? thanks.