Artist's commentary
Dom (and Gangaru)
I drew a fanart of Dom (Space Harrier) in the Dom Day.
Ten(十) can be read as tou(トウ) and six(六) can be read as muttsu(ムッツ). Therefore, October 6 is the ドム(Dom) Day.
The child post is Gangaru, modeled after the real plamo photo rather than the box art.