You'll pick this one up automatically as you drive near a monolith in the middle of the Voeld map.
Home in on the signal to find a fallen meteorite (the only kind there are, really).
Something about its rush with the Scourge enrages the local wildlife. Fight off the adhi until you have enough breathing room to scan and then dampen the meteorite.
Exercise caution- if you have to retreat from the site or are KIA, you may have trouble interacting with the meteorite again.
When done, you'll have the choice to either take the meteorite to the Tempest for study, or leave it as too dangerous. There are no known consequences either way, so follow your gut. In this case, it's probably better to follow SAM's advice- even the evil rock does do something horrible, Ryder will probably be the one to fix it anyway- might as well have it close to hand.