The Outer Worlds

One of the earliest Mega creatures you can find, and also one of the easiest, is a Mega Sprat that is underneath the Edgewater Landing Pad.

It has 1,463 health and I was able to whittle it down easily with a slightly upgraded hunting rifle, although I'm sure almost any gun could take it on.

As an added bonus, if you head over at night they will be sleeping making it easier to position and get a clean first shot off.

- Mega Creatures are basically chonky versions of the smaller enemies

- The easiest Mega Creature would be the Mega Sprat which you can find pretty early
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- It is hiding underneath the Edgewater Landing Pad, as shown in the video

All of my HD Achievement Guides for The Outer Worlds can be found here! :) (Mobile Friendly)
https://www.bradleafsfan9.com/the-outer-worlds

You find several Mega's later on in the game, I've found two already on Monarch, but you can get one in the Emerald Vale as well. This is located outside of Edgewater under the Landing pad, and can be killed easily at level 3 with the Companion. Hope the videos helps!

The achievement unlocks when you kill your first mega creature. There are two types of mega creatures. First, there are creatures whose designation is preceded by 'mega.' There are mega-sprats, mega-canids, mega-primals, mega-raptidons, and mega-mantisaurs. Additionally, there are unique 'named' creatures that fall in the mega category.

The first such named creature in the game is the mega-canid, Orthrus. He can be found in Emerald Vale on the left side of the road as you travel it from the Community Center to the Geothermal Plant. He is out in the open and is likely, but not necessarily, to be the first mega creature you will encounter in the game. You do not need to kill him but, if you do so, you will unlock the achievement.

If you are at a low level and, especially, if you are playing on Supernova difficulty, you may want to use a ranged attack. The hunting rifle, preferably but not necessarily with the Mag-2-Power plasma mod installed, is ideal. Starting outside the Community Center main entrance, follow the road in a northwest direction until you reach a junction. Turn left at the junction & follow the road a very short ways as it veers roughly to the southwest. You will hear several canids. They won't bother you as long as you stick to the road. If you look at the largest canid, purple in color, through the hunting rifle's scope; it will be identified as Orthrus. At night, they will be asleep to give you some advantage. Even though they're asleep, you will hear the sound of their growls.

Turn right off the road and target Orthrus at the extreme range of the hunting rifle. If you have Parvati as a companion with you, direct her to a safe spot behind you by pressing . If you are playing on supernova, ensure her behavior is set to passive and her range to far. Zoom in by pressing . Go into tactical time dilation (TTD) by pressing . Without moving from your spot so as not to deplete the TTD gauge, shoot Orthrus by pressing . It will take several shots but Orthrus should succumb before you have to reload the 6 round magazine. If TTD runs out, you should be far enough away to continue firing safely until you kill the beast. If this is the first mega-creature killed, the achievement will pop.

Once Orthrus is dead, sprint in a northwest direction away from the other pursuing canids. They will quickly lose interest and return to their starting point since you targeted the pack at an extreme range. You can then return to your firing point and dispose of the remaining canids. If you are playing on supernova and are still at a low level, you do not want to be surrounded by these multiple, powerful canids.

Orthrus, like all mega-creatures, will drop quite a few items of valuable loot. If, after you kill the rest of Orthrus's pack, you inspect their area; in addition to the loot, you will find a data tablet with an article entitled "Ethology Log: Hunting Behavior of Feral Canids." Read it to learn a little lore.

In addition to Orthrus there is an unnamed mega-sprat underneath the landing pad next to the town of Edgewater. If you go poking underneath the landing pad when you get to Edgewater, this will be the first mega-creature encountered but, unlike Orthrus, is not out in the open and will remain hidden unless deliberately sought out. Because of the difficult terrain, it is more difficult to engage safely compared to Orthrus, especially since it is accompanied by a number of feral, rabid sprats.

If you investigate at night, the sprats will be asleep and you will be able to unleash at least one powerful sneak attack before they are alerted. As with Orthrus, try to target the mega-sprat at the furthest possible range even though the environs are not very conducive to sniping. If this mega-sprat is the first mega-creature killed, the achievement will pop.

Once you reach Monarch, there are quite a few mega-creatures including four mega-mantisaurs in close proximity to one another and two mega-raptidons--one to the east of this group and one to the west. By this point, you should have leveled up to the point where killing them is routine even on supernova difficulty. If you exit Fallbrook and turn left into the river, a little upstream, you'll find a mega-mantiqueen on a small island.

North by northwest of that island, you'll find another mega-mantiqueen in the abandoned relay station compound. If you go up the dirt passageway to the immediate northeast of the relay station, you'll find a third mega-mantiqueen. To the east of that mega-mantiqueen, you'll find a unique named mega-mantisaur soldier, Karkinos. The game will alert you that you have found the Mantisaur Lair on the map.

The sidequest, Mandibles of Doom, on Monarch, requires you to kill a mega-mantiqueen as part of the mission. The quest is activated either by talking to the mercenaries at the C3 barracks just southeast of the Devil's Peak summit or by entering Devil's Peak Caverns and hearing Berthold Fox shout to you from a cliff. Follow the quest marker to the mega-mantiqueen and kill it. Berthold Fox will congratulate you. If this is the first mega-creature killed, the achievement will pop.

There are numerous mega-creatures in the game. In addition to those you'll stumble across while exploring, Nyoka's companion quest, Star-Crossed Troopers, will lead you to a regular mega-primal and the unique, named mega-primal, Col. Butterscotch--both marked by quest markers on Scylla. On Byzantium, the sidequest, Cupid of the Laboratory, given by Giles outside the tunnels requires you to find and retrieve a number of lab sprats. One of them, Harun Greenlee, is identified by a quest marker next to the unique, named mega-sprat, Kobalos.

In short, there are many opportunities to kill a mega-creature. Some of them are more involved than others. So the player can pick and choose when, where, and how to unlock the achievement. The first mega-creature can be killed at any point during the game including during the first hour of play. Alternatively, the player can wait till later when the player-character is at a higher level and better armed and when mega-creatures are more prolifically found.