Dat Boi, a colloquial pronunciation of “that boy,” is a nickname given to a 3D character model of a green frog riding a unicycle, typically accompanied by catchphrases like "here comes dat boi!" and "o shit waddup," that went viral on social media in early 2016.
source- knowyourmeme.com
It’s a new spiciest of frog and the sound it makes is he be rolling down the street and he will fuck your bitch in the sink he come dat boi shit wat up