“Rubbadub is a delay effect plug-in designed with versatility in mind. As a dub delay, it can be tempo synced and offers a state variable filter in the feedback line.
At the lowest extremes of delay line lengths, Rubbadub becomes a through-zero flanger with a variety of modulation options.
Time is split up into three modes (H, M, L) to provide detailed control over delay time, and even finer control is possible with the command key.
When modulation is pushed to the limit your sound transforms into a rubbery gelatinous substance that defies description.”
Source : ccrma.stanford.edu