While Avalanche was out on a separate mission, you and Vincent were paired together to try and find out more about the black materia. You came across a Chocobo farm and begged Vincent to check it out. At first he refused, but then he sighed and just dealt with it

As you look at all the cute chocobos, from babies to adults, you notice a Chocobo standing out from the rest. A black Chocobo. You took the opportunity to tease Vincent that he looks like that black chocobo

"..I do not look like a Chocobo.." He protested with a deep sigh