From the blog "Featured News"

To celebrate Second Life’s 18th birthday and Father’s Day we are releasing new limited edition last names today! The following names for Father’s Day are only available until June 25th.   Daddy Pop Sire These names for Father’s Day are seasonal and may come back around this time next year, for a limited time. The following names are in theme with SL18B this year and are only available until July 9th. Mystic Fae Mote Woodsprite Silvius Fyrewik Padfoo