Simplify the following text for a Grade 8 native English-speaking person.
Original: OpenBSD at first used the BSD daemon mascot created by Marshall Kirk McKusick . Subsequent releases saw variations , eventually settling on Puffy , described as a pufferfish .
Simplified: OpenBSD 's first mascot was a BSD daemon with a halo , it was replaced with Puffy , a pufferfish , on June 15th , 2000 , with the release of OpenBSD 2.7 .