Diy Trio Costumes . 21 mario, luigi, and toad. Most friends costumes tend to feature the girls of the group, but a fun option for parents with a new baby is to dress as the show's most iconic couple—plus ross's pet, marcel the monkey. Trio halloween costumes, Halloween costumes friends, Bff halloween costumes from www.pinterest.com Scroll on for our ultimate guide to easy halloween costumes. Its so easy to diy and just sort of perfect. Halloween is always better when your favorite people are all together.