Probe Entertainment, formerly Probe Software was a video game developer from Cheltenham, England founded in 1984. They were later owned by Acclaim Entertainment becoming iguana London for a short time, Acclaim Studios London during 1999-2000 and finally Acclaim Cheltenham until 2004.
Probe UFO is a reference for Probe Entertainment. It's like a mascot for the company and appeared in the introduction of various other Probe games, Extreme-G 2 for example.
Hidden "Probe.m" as seen in a 3d modeler