Source: Unearthed Arcana 8, Ranger

As a ranger of the Stalker path, you prowl the wilderness in search of aberrations, fiends, and other monsters that must be slain before they wreak havoc on the natural world. You are the power of nature’s vengeance made manifest, and anything that poses a threat to nature is your target. When a powerful creature such as a dragon threatens a region, a ranger of the Stalker path leads the hunt that will take it down. Like others of your kind, you do not rest until your
quarry is dead and the natural world is safe.

When your spirit companion manifests, it takes the form of a dire wolf.

Stalker’s Fangs

Your companion spirit lends the strength of its deadly bite to you or one of your companions. As a bonus action, you invoke your spirit companion and choose yourself or a creature you can see. The next time the chosen creature hits with a weapon attack, the target of the attack takes extra slashing damage equal to 2d6 + your Wisdom modifier.