Stop hitting on me, I'm really shy

The natives advanced superweapon was extremely effective in battle, but they all died to various diseases like smallpox anyway.

I haven't seen most of the third season yet, but "Bad Travelling" was pretty on point if what you're looking for is Lovecraftian horror. (The recurring episodes with the three robots are pretty dumb, though.)

Love Death Robots is a very hit-or-miss show, particularly in earlier seasons, but when it's good, it's really good.