Supramolecular bonds have been widely used for designing polymers because of their reversible nature. In contrast, utilization of their dynamic equilibrium nature to access materials of unusual mechanical properties has been poorly explored. Taking full advantage of this latter attribute requires the design of polymer networks with high contents of supramolecular bonds. In this work, polymer networks with high contents of self-complementary hydrogen bonds (ureidopyrimidinone) are synthesized using thiol-acrylate click addition. The excellent tunability of the network allows a range of intriguing mechanical properties to be achieved including the transition from plasticity to elasticity, ultrasoft shape memory polymer, strong strain rate dependence, and high mechanical damping. Materials with such versatile dynamic behaviors may open up a range of new applications.