another shape of LESS mixins that is vaguely like inheritance in scripting languages

In addition to what I suggest here, another definition for a mixin would be this sort of thing:

#seaMonster {
   background-color: #000000;
   color: #00FF00;
}
#cthulhu {
   width: 1000px;
   height: 1000px;
   #seaMonster
}

 
 

All of the styles in #seaMonster will get put into #cthulhu this way when the CSS gets rendered out.