you just copy and edit it, then go into graphics.c (for hot glow) and put if(ptype.prop==PROP_HOT_GLOW) then copy the code from something like lava, to get the hot glow part.
not sure if the ptype.prop bit is right, but it's somehting like that.
Otherwise, you'd go into another cfile and add the programming for what you want to do if it has that certain property.

@Diissaster
yes, where the others are, somewhere below the element defines list.