Hamadryad

Hamadryads, akin to regular dryads, are normally just as shy and seclusive, but are pointedly not guardians of the forest as a whole; only ever being bonded to a single tree, their lives intertwined. Only one is ever encountered, during Baldur's Gate in the Fourth Cloakwood, and it is always hostile; it's unknown exactly why, as most Dryads are relatively friendly, though the recent activity at the Cloakwood Mine to the east could be reason enough.

The Hamadryad can be a very evasive enemy, casting Dimension Door to evade the player's party, while casting several spells - 2x Dire Charms, 2x Hold Persons, and 2x Entangles - before eventually engaging in melee combat. It is immune to all magical damage as well as having a resistance to missile damage, and it's fairly difficult getting close enough to attack with melee weapons due to the repeated Dimension Doors, though the teleportation is short-range and predictable. It also has fairly high saving throws, so most spells and abilities will likely not make a difference.

Quotes

 * "The very trees cringe at the sight of thee."
 * "Nature knows much of you."
 * "Leave my wood!"
 * "Do as I bid"
 * "Thy will is mine!"