<jats:p>A new indolyl-6,10b-dihydro-5a<jats:italic>H</jats:italic>-[1]benzofuro[2,3-<jats:italic>b</jats:italic>]indole derivative, varioloid A (<jats:bold>1</jats:bold>), was isolated from the marine alga-derived endophytic fungus <jats:italic>Paecilomyces variotii</jats:italic> EN-291. Its structure was elucidated on the basis of extensive analysis of 1D and 2D NMR data and the absolute configuration was determined by time-dependent density functional theory-electronic circular dichroism (TDDFT-ECD) calculations. A similar compound, whose planar structure was previously described but the relative and absolute configurations and <jats:sup>13</jats:sup>C NMR data were not reported, was also identified and was tentatively named as varioloid B (<jats:bold>2</jats:bold>). Both compounds <jats:bold>1</jats:bold> and <jats:bold>2</jats:bold> exhibited cytotoxicity against A549, HCT116, and HepG2 cell lines, with IC<jats:sub>50</jats:sub> values ranging from 2.6 to 8.2 µg/mL.