A wraith is a special type of bug. It can be identified when it teleports in front of you. It will make your screen hazy and it usually emits a high-pitched screech right as it teleports.
Anyways, you kill one before it re-stealths, you can use your Impact ability to knock down the wraith. As it lays on the ground you should take your hammer and pound it into the ground. It may take a second whack, but you will pop the trophy once you extinguish the bug.