Summary
Subnauticais a game filled with options and isnotable as a survival gamewhere almost no creature ever has to be fought or killed if the player chooses not to. However, there are ways to take on the giant creatures that inhabit the oceans of the alien planet the player crash lands on.
While it is nearly (but not quite) impossible totake down a sea dragon, the smaller ghost leviathans and reaper leviathans can be killed by the player using only the limited weapons they are allowed to craft in-game. From the obvious to the entirely insane, themethods to tackle and end a reaper inSubnauticaare many.

Updated on February 25th, 2024, by Chris Harkin:With another Subnautica game well on the way this year, it is a great time to revisit the decade-old survival game which doesn’t feel like it has aged a single day. Reaper killing is a favorite pastime for many players who have completed multiple runs of the first Subnautica, and finding new and inventive, perhaps even crazy, ways to tackle these monstrous creatures is an interesting task for those who deep-dive into what is possible within the wide open waters of this alien planet. Reapers certainly aren’t easy to take down, but players can use these methods and try to find their own original ones in the pursuit of becoming the master of reaper hunting.
7Prawn Suit Drill Arm
Works Best Alongside The Grapple Arm For Grab & Drill Technique
While the prawn suit is something of a safety net against thegiant creatures that roam the world ofSubnautica, it can only take two or three hits from a reaper before being destroyed. Fortunately, during reaper fights, the creature will usually attack and then wander off for a while, giving players the opportunity to repair the suit between charges. There are many possible attachments for the prawn suit, but the most common pairing for fighting will be one drill arm and one grapple arm.
This combination allows players to latch onto a reaper leviathan and not let it get away, providing them with an opportunity to kill it much more quickly than in an elongated battle involving many charges from the reaper. The drill arm is a hugely useful tool for inflicting damage on these massive creatures. Drilling constantly into this beast while latched on with the grappling arm is an effective technique and will provide results, quickly eliminating reapers and even the bigger leviathan class beings as well.

6Stasis Rifle/Thermo-Blade
The Slow-But-Steady Classic Method Lacking In Major Machinery
This method appears at first glance to be the most insane of all ways to fight a reaper inSubnautica. However, it is actually one of the safer and more assured ways to end one. The stasis rifle is a weapon that can freeze objects in the game into place for up to thirty seconds, and the thermo-blade is one of the few tools that can actually inflict damage on an opponent.
While there is very little safety involved in the process, using the stasis rifle on a charging reaper leviathan can hold the creature in place while the player goes beneath andattacks with the thermo-blade. Slashing away at the underbelly may not feel as effective as attacking in a prawn suit, but it is easy once the player has the technique down to hold the reaper in place indefinitely. When the bubble of the stasis rifle shot starts to flicker, it is time to stop slashing and throw another shot with the rifle to continue holding the reaper in place. If using a normal knife to slash, it will be a slow process, but with a thermo-blade, the reaper will be dead in just a few minutes of slashing at it.

It’s important to bring medical kits when using this method since it takes a reaper two hits to kill the player. Players should also make sure to go up for air when necessary or to have another way to breathe at hand.
5Prawn Suit Torpedoes
Trickier To Hit With But More Rewarding When They Strike
Prawn suits have other attachments that provide other means of fighting and killing a reaper. However, it can be dangerous and messier than using grappling and drill arms.Subnauticadoesn’t provide traditional missiles or torpedoes, but it does give players the option to create gas torpedoes. These will explode on impact and release powerful gas fumes that can kill even a reaper leviathan. However, each arm in a prawn suit can hold a payload of six gas torpedoes, and even at maximum damage, each torpedo can hit a target for around 500-550 damage.
This means players will probably need to make both arm attachments on their prawn suit into torpedo arms and fill both with gas torpedoes. Even then, reapers are infamous for their lack of staying still unless hit with a stasis rifle blast. Players can attempt to let a reaper get close and then stasis rifle it before getting back into their prawn suit to fire all of their torpedoes before the creature escapes the rifle blast. This could definitely kill a reaper, which has 5000 health and could be eliminated by taking the full damage from 10 torpedo clouds. With 12 total torpedoes in the payload, it is likely it would die, but unlikely if the reaper is allowed to move during the attack.

4Just The Prawn Suit
For Players Who Love A Grindy Challenge
The prawn suit is frustrating when first gotten inSubnautica. Without upgrades like the grapple arm in particular, it is hard to move longer distances in the frustratingly low-mobility machine. For this reason, it is quite the challenge to go in against a reaper using a prawn suit and nothing else. No upgrades or extra arms for the suit, no torpedoes, just the suit versus a reaper, is a pretty tough challenge.
Reapers can damage a prawn suit, and players can use a repair tool to get out and fix it if they think they have time before the reaper circles back around. The bigger issue is damaging the reaper without being able to grapple onto it. This means players need to strike consistently when the creature is near, but avoid taking too much damage. The erratic movement of reapers is difficult to work against when fighting them, making the lack of stasis rifle or grappling arm the biggest part of this challenge.

3Seamoth Torpedoes
Can Usually Be Done Earlier In The Game
If players want a real challenge, it is possible to kill a reaper with a Seamoth. The fast vehicles seemgreat at speedy underwater travel, but it is still difficult to avoid a charging reaper in one, and a Seamoth cannot take more than a couple of reaper strikes before exploding. Fortunately, players can also attach a torpedo system to the Seamoth, which will damage a reaper.
However, the Seamoth torpedo system maxes out at 6 torpedoes. It is possible to make all four Seamoth attachments into torpedo systems for a total of 24 torpedoes, but this makes the Seamoth hugely vulnerable to attack. If quickly fired at the right time, this large set of torpedoes can kill a reaper, but the Seamoth is definitely a vulnerable tool to rely on in such a fight.

2The Lone Knife
For Hardcore Players Who Love A Challenge
A game likeSubnauticacomes with all sorts of challenges that players love to come up with, and one that will test the limits ofSubnauticaveterans' gameplay and patience is attempting to kill a reaper with a knife or thermoblade, minus the stasis rifle that makes that more common fighting method so popular and much easier.
It is possible to knife a reaper leviathan to death without the stasis rifle holding them in place, but it takes much longer and is much more challenging.Reapers swim faster than the playerand charge often if said player stays near them. Attempting not to get caught is the challenging part, but even if the player can use a mixture of speedy items like fire extinguishers, air bladders, and more to avoid the stampeding giant, they still have to get enough knife strikes in to kill it. This is a long and slow method, and the stasis rifle is highly recommended before a player attempts to knife a reaper to death, but it is viable and a highly intriguing challenge.

1The Cyclops Shove
Suicidal And Only For Crazy Players, But It Can Work
The Cyclops is usually more of a big target for reapers to attack than a tool for their destruction. Decoys to escape reapers replace the opportunity to fire missiles at them, butthe Cyclops can kill a reaper. The Cyclops causes damage inSubnauticawhen it hits creatures in the water. This can result in smaller creatures being accidentally killed when they are caught in the path of such a large vehicle. A reaper will also take a chunk of damage when the Cyclops hits it. Usually, this doesn’t matter because the Cyclops will take much more damage, but with a shield generator on the vessel being activated just before the reaper hits, the reaper will still take damage, but the Cyclops will not.
Shields take a huge amount of energy. So, for this method to succeed, it is almost necessary to use ion power cells over regular ones. Even so, players will need to turn the shield off between reaper charges to find success. Going at high speed into a reaper like this for several minutes can kill it, but the method is hugely dangerous since a Cyclops is difficult to replace.