Back to India we go today! An inquisitive question-asker wants to know: Are there any avatars of Shiva? And indeed, there certainly are, and we would love to talk about them!
Shiva has an interesting relationship with avatara - at least, in contrast to Vishnu, who is pretty universally understood to have various avatara which are carefully catalogued and widely known. Shiva, on the other hand, may or may not have avatara of his own, depending upon who you ask; different sects of Hinduism and local traditions of worship have different opinions on the matter, which means that who's "correct" is a matter of religious debate.
In several sects, Shiva is not officially recognized to have any avatara; this is especially prevalent in Vaishnavism and other groups that are particularly excited about Vishnu, since they often treat the concept of avatar as something solely associated with Vishnu, or might consider Shiva primarily an emanation or version of a different deity rather than considering him on his own. In other cases, Shiva might be considered so singular and universal that he has no need of avatara. On the other hand, other branches of the religion name many avatara for Shiva, and at least two different scriptures, the Linga Purana and Svetasvetara Upanishad, list a number of avatara for him. (And that's not even counting the alternate forms of Shiva that are deities in their own right, like Rudra or Bhairava, but I think your question was asking about lower-level avatara. I hope I'm right!)
Anyway, so yes, there are definitely avatara of Shiva in various Hindu traditions, although they aren't all accepted across all branches of the religion. Different sources give the number of avatara as anywhere from four to eleven to nineteen to twenty-eight - obviously too many for one blog post, but we'll cover a few!
First up, we have the powerful and excessively dangerous Ashwatthama, who in the Mahabharata was born to the royal sage Drona after he performed many years of unceasing meditation and asceticism to honor Shiva, and then asked the god for a son that would have the same strength as Shiva himself. Shiva then icnarnated himself and was born as Ashwatthama, who did indeed bear an eerie similarity to Shiva; he was considered the most powerful among the warriors of the great battles in the epic, was said to be skilled in every weapon in existence, and had a jewel in his forehead that gave him great powers, similar to Shiva's third eye.
Ah, yes, riding in a war chariot, shooting people with deadly arrows... seems familiar.
Interestingly, just as Shiva and Vishnu sometimes serve as foils for one another on a divine scale, so do their avatara in the Mahabharata. Ashwatthama is friends with Arjuna and the Pandavas, along with Arjuna's best buddy and renowned mischief-maker Krishna, avatara of Vishnu, but he is tricked into becoming angry with them because he believes that Arjuna is competing with him for his father's regard. It's been foretold that Ashwatthama cannot be defeated in battle, however, because he's just too powerful, so the Pandavas lie to his father and tell him that Ashwatthama has been killed, causing him to give up in despair. The Pandavas kill him while he's being despondent and not defending himself, which, as anyone could probably have guessed, causes Ashwatthama to go on a massive murder spree, eventually blowing up the Pandavas' camp (fun tri-layered fact: he first speaks to Shiva to ask him for help in his attack, and then Shiva grants that wish by manifesting as Bhairava and possessing him, the Annihilator, so in this scene we have Shiva asking Shiva for help, and then Shiva helping Shiva by transforming into Shiva and possessing Shiva. Classic!).
By the end of the war, Ashwatthama is the only survivor of the entire violent episode, but unfortunately for him, Krishna curses him for his misbehavior, so he's forced to spend the next three thousand years wandering the forest, bleeding and wishing he could die, so really no one ends up happy.
One of my personal favorite avatara of Shiva is Sharabha, who is one of Shiva's more radical avatara (and that's saying something). Sharabha isn't humanoid at all, nor is he any kind of natural animal; he's an eight-legged super-monster with the ability to defeat any animal in existence, composed of parts of deer, birds, or giant cats, capable of leaping entire mountains and swallowing entire herds of lesser creatures. And if that's not fun enough, the reason Sharabha exists in the first place is because Narasimha, the lion-warrior form of Vishnu, got out of control and was on the brink of a rampage, so naturally the gods decided that the solution was to make an even bigger, meaner monster to go sit on Narasimha until he calmed down.
Which, as you can see, is exactly what he did. Much has been written about how the conflict between Narasimha and Sharabha mirrors the way Vishnu and Shiva are themselves at odds sometimes, and on a mortal level also mirrors the traditional rivalry between Hindu sects devoted to one or the other. In fact, in regional variants, sometimes one of the two gains the upper hand and sometimes the other does, depending on who's more popular in the area.
And then there's the perennial fan favorite Hanuman, monkey warrior and incorrigible danger to the universe, a hero with innumerable magic powers who generally doesn't remember that he has them and tends to solve all his problems by setting things on fire. Although Hanuman is traditionally the son of Vayu, god of the wind, he's also an avatara of Shiva; some versions of the story claim that he's only one or the other, but when he's both, usually the story goes that his parents fervently worshiped Shiva and asked him for a child, so Shiva asked Vayu to place some of his divine essence in the woman's womb, at which point Shiva inhabited it to make the resulting child his avatara.
We blogged about Hanuman at length recently, so I won't go super into detail on him, but suffice it to say that he's ridiculous, hilarious, and capable of destroying everything if the need arises. Just as we would expect of an Avatar of Shiva!
There are plenty of other avatara (or potential avatara that folks don't always agree about), some of them even stranger - for example, Shiva's vahana, the white bull Nandi, is occasionally considered an avatara of Shiva as well, thanks to the fact that it was Shiva who caused Nandi to be born and who imbued him with immortality as well. But to try to go into them all would eat up a lot of days - so for now, we're signing off!