A new study by the MP2Lab on the bioactivities of the mucus of the tropical sea slug Elysia crispata has been published in the journal Molecules. In this study, the antimicrobial, antioxidant, and anti-inflammatory activities of the mucus were assessed. Inhibitory activities against several bacterial strains were observed, more pronounced for Gram–negative bacteria. Particularly interesting was the strong inhibitory effect of mucus protein extracts against Pseudomonas aeruginosa, a bacterial species classified by the WHO as a high-priority pathogen and associated with high-risk infections due to its frequent multidrug-resistant profile. This study opens the way to further research on the biomedical applications of the mucus secreted by this unique marine organism, particularly as an antibacterial and wound healing agent.