Unlike with gigas you can easily get this by killing a wild carcharo in this process that takes little resources:

1. Find a carcharo that you dont want existing* then get the carcharo to trust you:

1a. Carry a wild t rex or paracer** with a rhynio and find the carcharo

1b. Drop it in a spot where the rex's corpse wont roll away close to the area where the carcharo is then set your rhynio to passive*** and make sure there are no argies or anything in the area that would run at your rex corpse and harvest it

1c. Kill the rex, then make your rhynio land directly on top of the rex's corpse

1d. Dismount so that the rhynio will phase into the body then mount the rhynio again and press drag body (this may take a few attempts)

1e. While keeping in mind that from now on until the carcharo sniffs the air then eats the corpse your rex corpse is very vulnerable to any argy or dino that can reach high enough to harvest your corpse****, lure the carcharo by either flying very slowly until you reach it and it sniffs the air and harvests the corpse, OR fly high enough from the ground so that you are out of the carcharos bite hitbox, then aggro the carcharo by shooting it and when its under you wait for the aggro to end (indicated by the carcharo sniffing) then the carcharo will sniff then eat the corpse and your rhynio will most likely tank some damage from the carcharo*****

2. Mount the carcharo and ride it off cliffs until it dies or until it reaches low enough health that you can finish it off quickly with a tame****** then boom you will get a free giga heart and exp while using the least amount of resources

* This can be for a few reasons, e.g. its a low level, you want its exp or you need a giga heart

** Paracers are harder to get since you need to fly to the redwoods or a swamp but they dont attack you when you are flying, if youre transporting a rex you can do a few things:

1. Use the scream attack against the rex, and start carrying it until the effect wears off and the rex starts attacking you again, then drop it and use scream attack again, repeating the process until you reach the spot where the carcharo is, note that the rex will start attacking you again before the scream cooldown finishes.

2. Use the resin armor ability and just tank the damage while flying until you reach the spot where the carcharo is, you can also hoard stacks of cooked meat if the rhynio gets low so you can drop the rex then spam heal since cooked meat heals more than raw meat

3. You can strafe left or right so that the rex's head turns away from your rhynio and cant attack it so basically you are flying perpendicularly to the spot where the carcharo is

*** This is to make sure your rhynio wont harvest the corpse when you dismount

**** There are a few reasons why you are vulnerable:

1. You move very slowly while dragging the corpse

2. You cant let go of the rex corpse without dismounting from your rhynio due to the rex corpse constantly swinging around in your rhynios grip

3. Unless you are quick with a shotgun or any gun with high dps in your hotbar (this is probably your best bet against other dinos due to the very slow movement speed) your rhynio can't do any melee attacks except for the sap attacks without the rex corpse being in the attack hitbox which results in the corpse being harvested by your rhynio.

***** If you are in an area where the corpse wont roll away you can also dismount and mount after the sniffing animation starts to drop the corpse

****** You can attack wild carcharos that trust you with tames and they wont attack back, wild carcharos that trust you also can't damage tamed creatures (but they can damage unclaimed creatures)

Some things to note:

1. If you dont want to find and carry a rex or paracer you can also kill and drag mammoths if your carcharo spawned in a snowy area but this is way harder since you need 2, you need to feed them to the carcharo quickly since one only gives 80% trust, the trust percentage depletes over time quickly, and they need to be killed in places that are distanced away from each other in case the carcharo decides to eat the second one in its aggro range after eating the first one giving no trust percentage for the second one

2. You need to make sure that the carcharo sniffs the air before you can feed the corpse to it, there are no exceptions because in any other case the carcharo will just eat the corpse and it gives no trust percentage