Soundgarden - Jesus Christ Pose
This riff isn't very demanding technically, it can be played with just two fingers (or even one if you're feeling adventurous), but the rhythm is a bit trickier than it first seems. Even though we mainly play sixteenth notes on our right hand, the placement of the notes on our left hand will make up the rhythm and groove of this riff. And with a tempo of 134 bpm, it's not always easy to put or remove your fingers at the right time. So be sure to start really slow, and speed up very gradually making sure you don't miss a single note.
To really get that haunting feeling out of it, watch carefully the regularity of your sixteenth note, and add a little dab of palm mute (but not too much, we're not playing metal here). A nice heavy and dark distorsion will be the only ingredient missing for you to groove the hell out of this riff.
Do note that the original song is played in Drop-D, but since that particular riff is entirely played on the low D string, you're free to play it in any tuning you want, you'll just end up a bit higher or lower than the original.