HELPPPP! shes H O T

so I took my 1974 swinger 360 auto out last night and my Head lights were turned on, a guy pulls up to me and tells me my brake lights are out, I pull into the gas station and sure enough both bulbs are burnt out, I look in the floor of the car and here is this burnt plastic with a light bulb in it, (pic attatched) then I look at my dash cluster and the voltage is pegged at positive and it looks like it has burnt from the inside out the plastic has turned gray and the plastic is burning hot!!!! also my tach that I added was burning hot as well...... :banghead: WHAT DA HELL IS GOING ON?