Finned JellyfishA Finned Jellyfish occurs when there is a Jellyfish with additional candidates.
In the sudoku diagram below either in the R9C3 cell (marked in yellow) you can place the digit 8 or there is a Jellyfish i.e. in the first, fourth, sixth and ninth rows the digit 8 can only be placed in the first, second, eighth and ninth columns (candidates marked in blue). Thus, we can eliminate the digit 8 from the remaining cells of these columns, which simultaneously see the cell R9C3, so from the cells R7C1, R7C2, R8C1 and R8C2. After applying this technique, the digit 8 in the bottom left box can only be placed in cell R9C3.