[Rolando]

In the cthulhu mythos there are some creature or entities that can be summoned, there are formulas or spells to summon them.

Also protections against them, but not always effective or easy to use as a pentagram.

There are the dimensional shamblers, tindalos hounds, and many others, each entity traditionally have a spell or formula to summon and another for protection...if any.

Also, summoning one not necessarily means controlling it, sometimes a different formula/spell is needed for control.