I think you are looking for a preset, as opposed to an effect?

You can find a list of the Artist, Song and factory user presets in documents linked at the bottom of this FAQ page:  http://line6.com/support/docs/DOC-1538

I think you want 'Froggy Night, which is in the factory user preset bank 12, A channel.  If you have already written over this location with your own preset, you can find it in the 'D Torn' (David Torn) artist location - there are a bunch of 'Frog' tones!