To get DeadGoa7 go to the tallest building and inside the lobbie you will find the lift. Go inside the lift and you will be transported to the top of the building where a party is happening, head butt the DJ wearing the mouse head and you will transform into DeadGoa7

To get antigravity goat find the black circle inside the construction site ( second floor ) then take it to the green pipe. Once inside, go to the fan room and into the little box on the side. This will shoot you out of a whole and give you antigravity goat