A galaxy that shows some exceptional features in addition to the type assigned to it in schemes such as the Hubble classification (and is given the suffix p or pec), or a galaxy whose structure is so unusual that it defies classification. M32, the small elliptical companion to the Andromeda Galaxy, is classified as peculiar because it appears to have had its outer regions removed in gravitational encounters with its massive neighbour. M82 in Ursa Major appears to be an edge-on spiral encountering a massive cloud of gas and dust and undergoing a consequent burst of star formation.