You might remember North Sentinel Island from the news a few years ago. A Christian Missionary from America attempted to visit the island to preach and convert its inhabitants but was killed by a volley of spears upon setting foot on its shores.
North Sentinel Island is a disturbing anomaly. Mysterious people live on it, but all attempts to contact them have gone disastrously wrong, and they attack any outsiders with unparalleled ferocity.
Shout out to @panzergen for the suggestion.
BONUS Video -
Keep suggestions coming. Keep them classy. No butt stuff.