Chemical examination of the solid culture of the endophytic fungus Stachybotrys chartarum isolated from the sponge Niphates recondita resulted in the isolation of 16 new phenylspirodrimanes, named chartarlactams A-P (1-16), together with eight known analogues. Their structures were determined on the basis of extensive spectroscopic analysis, including X-ray single-crystal diffraction for the determination of the absolute configurations. The isoindolone-drimane dimer chartarlactam L (12) was determined as a new skeleton. Compounds 1-6 and 8-24 were evaluated for antihyperlipidemic effects in HepG2 cells, and the primary structure-activity relationships are discussed.