"Hello, Arnie ... Arnold Peasegood, he's an Obliviator — member of the Accidental Magic Reversal Squad, you know"
-- Arthur Weasley's running commentary on Ministry of Magic personnel (GF7)
Arnie Peasegood was an Obliviator and trained Hit-Wizard for the Accidental Magic Reversal Squad (GF7).
Arnie arrested three goblins at the Chipping Clodbury riot and suffered a minor attack of boils (DP3).
He is pointed out to Harry and Hermione and greeted by Arthur Weasley at the 1994 Quidditch World Cup (GF7).
He may be a descendent of Abraham Peasegood, an American wizard who invented the game of Quodpot in the eighteenth century (QA8).
Other canon notes and references
The Accidental Magic Reversal Squad is a division of the Department of Magical Accidents and Catastrophes located on Level 3 of the Ministry of Magic.
Arnie is short for Arnold, which means "eagle power" (from arn "eagle" and wald "power") (Behind the Name).
Peasegood is an Anglo-Saxon surname and means "peascods" (pea pods). It may have originally been given to sellers or growers of peascods (Internet Surname Database).
While the date printed on DP3 is 1 June 1999, the timeframe for these events is 1992-1993.