This study presents a simple fabrication process for slippery liquid-infused porous surfaces (SLIPS), where the conventional intermediate step of forming porous structures on the substrate is eliminated. The fabrication process is lithography-free and based solely on the oxygen plasma modification of the Parylene C (PAC) on the silicone oil structure. The resulting surface, referred to as PAC-Oil SLIPS, displays a 30% PAC porosity with an averaged pore size of 180 nm and a superhydrophobic water contact angle of 150.3 ± 2.4°. The biofluid repellent properties of PAC-Oil SLIPS are demonstrated by the quick rolling off of water and porcine blood droplets on a slightly tilted surface (8°). Furthermore, the anti-biofouling capabilities of PAC-Oil SLIPS are evidenced by a significant 87% reduction in Escherichia coli (E. coli) biofilm coverage area compared to the PAC surface. These findings highlight the potential of PAC-Oil SLIPS in biomedical implant and catheter surface protection applications, where minimizing the risk of infection is paramount.