Damon Madsen's Rear Suspension

 and it looks like a very low p kickback as well

 i think it's a DW link reversed, i think the point is to tighten up the rear triangle/chainstay. i could be wrong.

 No, an additional link is less stiff. That lower link is required for the suspension to work.

 @theminsta: In theory you could add a secondary link that follows an identical path to the first one, which would not alter the way the system moves but simply provide a secondary point of constraint to resist torsional movement. In most cases it would be unnecessary, sure, but "an additional link is less stiff" is not correct I'm afraid.

 @bobj: You are correct as I should have used "that" instead of "an". The only bike that uses additional links for added stiffness that I can recall right now is the 2017ish GT Fury; an exception to the rule.