When all candidates for a specific digit in 5 rows are located in only 5 columns, we can eliminate all candidates for that digit in the other columns that are not located in those 5 rows. (And vice versa for columns/rows).
Translation: They are very difficult to detect. It is a jellyfish with an additional column or row (5x5x5x5x5; 5x3x2x3x4, etc).
The “excluded” cannot be between two cells of the Squirmbag.
In the Sudoku below: Row (3x2x2x3x4) or Column (2x2x2x3x5):
Another example, for the number “5”:
In the same sudoku, for the number “7”:
