Despite thin-line actuators becoming widely adopted in different Human-Computer Interaction (HCI) contexts, including integration into fabrics, paper art, hinges, soft robotics, and human hair, accessible line-based actuators are very limited beyond shape memory alloy (SMA) wire and motor-driven passive tendons. In this paper, we introduce a novel, yet simple and accessible, line-based actuator. ModiFiber is a twisted-then-coiled nylon thread actuator with a silicone coating. This composite thread actuator exhibit…