In order to gain this achievement, you must capture the
Prism Hercudrome. This creature is
Endemic Life available on many of the areas within the game, but it will only spawn at
Dusk or Dawn. In order to change the time of the day, just keep playing the game, and travel between Astera and your expedition until you get dusk/dawn. Endemic Life cannot be killed, and can only be captured with a
capture net.
They only spawn in specific spots, but the best areas to find them is in
Area 2 of Ancient Forest or
Area 10 of Wildspire Waste. They will spawn on a specific large tree, barely move, and are easily caught.
See the video for more information: