Carlo van Leeuwen crossed the Great South Run finish line in 1hr 09mins despite being dressed as the Cookie Monster.
The 35-year-old, from Itchen, was running to raise cash for The Motor Neurone Disease Association. He was inspired to help the charity after his father Cor died from the disease five years ago.
He has raised more than £8,000 over the past five years.
He said: ‘It was very warm in my suit, but well worth the effort.’
Carlo was joined by other MND Association fundraisers Chris Maple, 43, from Salisbury, who ran with a unicorn attached to him, and Gary Skerratt, 52, from Buckland, who ran dressed as Superwoman. Gary said: ‘It was a fantastic race. The crowds really keep you going.’
Other unusual fancy dress saw superheroes, First World War soldiers, SpongeBob Squarepants, werewolves, men dressed as Disney princesses and much more.