A verb can be appended to the γ-stem of a godan verb, altering the meaning.1
Example: To pass beyond
γ¨γγγγγ
Info
γ¨γγ is the γ-stem form of γ¨γγ (to pass through). It is in this form so that the following verb can be appended to it.
γγγ (to go beyond) is the verb being appended to the γ-stem of γ¨γγ. It is changing the meaning of γ¨γγ (pass through) to something more akin to βpass beyondββas though one is passing beyond the range of perception.