What is the black putty called that seals up the ac unit?

[BigTruckDriver]

I have changed out my heater core and had to move the ac unit.The ac unit is sealed up the fire wall ,I broke the seal when I unbolted it.I need to make the seal back,whats it called ,does any auto parts sell this stuff.

Man the heater system is really going to blow cant wait to turn it on .I also got a new blower for it also.The new heater core has bigger passages through it,so I am thinkin it will flow more air.

[BigTruckDriver]

It kinda looks sprayed on.There is the tape stuff wraped around the pipes.that is still intact.The stuff I need is where the housing meets the fire wall all away around the housing.