Jack "BaldDumboRat" Thatcher, also credited under the names JitterbugJive and PierceSmoulder, is the creator and director of Doctor Whooves and Assistant. He provides the voice of Derpy Hooves, which leads people to believe that he is female. He is a female-to-male transgender, and hates being wrongly accused of being female.
- BaldDumboRat is a female-to-male transgender, meaning he was born female and is physically female, but mentally and psychologically a male. Very few have the right to address his femininity.
- He has stated that he is Pansexual. This is made clear, since he is in a relationship with Jestre DeRama, the current voice of Doctor Whooves.