Bob Parr's superhero friend with ice powers is Frozone. His civilian identity is Lucius Best, a longtime friend of Bob Parr and a close ally of the Parr family.
Frozone can freeze liquid water and moisture in the air, creating ice slides and other structures for rapid movement. His abilities depend on available moisture, so dehydration can weaken him. His specialized suit and goggles help him operate in freezing conditions and protect his identity and eyes from reflected glare.
Frozone is more than a side character: he was Bob and Helen's wedding best man and joins the family in fighting Syndrome's Omnidroid. The character returns in Incredibles 2, where he helps battle the Underminer and later falls under the Screenslaver's control. A common mix-up is confusing him with Sub-Zero, Mr. Freeze, or Iceman; those are unrelated characters from other franchises.