Gnasher is a fictional character from the British comic strip "The Beano," which has been published since 1938. He is a pet dog belonging to the character Dennis the Menace, known for his distinctive spiky black fur and mischievous personality. Gnasher often accompanies Dennis on various adventures and is known for his loyalty and playful antics. Gnasher is characterized by his toothy grin and a penchant for biting things, which adds to the humor of the comic strip. He has become an iconic figure in British children's literature, representing the fun and mischief associated with childhood.