1) 18t indricotherium vs 18t songhua river mammoth
2) 650kg megalania vs 350kg amur tiger
3) 650kg megalania vs 2x 150kg lioness
4) 100kg komodo dragon vs 200kg wild boar
5) 100kg komodo dragon vs 80kg leopard
6) 18t indricotherium vs 4x 600kg utahraptor
7) 18t indricotherium vs 5t megatherium
8) 18t indricotherium vs 10,5t triceratops
1) 18t Indricotherium vs 18t Songhua river mammoth: For some time, the Songhua river mammoth was believed to be a rival to the Indricotherium for the title of "World's Largest Land Mammal Ever". It has since been determined that the Songhua river mammoth was actually a Steppe mammoth, and did not actually attain the sizes granted to it. Indricotherium relied on its great size to deter predators, and likely wasn't a practiced fighter against other species as a result. However, it's possible it may have been able to make an aggressive charge and perhaps deliver a kick (or bite) to any threat that got too close, but we don't know for sure. A Songhua mammoth has long curved tusks (probably not suitable to stab, but to apply force) to use as a solid offense. The mammoth will be better armed here, and the indricothere won't have a decent way to "block" the pachyderm's assault. These 2 will likely coexist quite peacefully in a realistic encounter, but the mammoth is better equipped to succeed in any hostile conflict. Songhua river mammoth wins.
2) 650kg Megalania vs 350kg Amur tiger: Megalania was a giant monitor lizard (but stockier) with similar attributes as modern-day ones (tough hide, sharp teeth, whip-like tail), and may have had a toxic bite like today's Komodo dragons do. Amur tigers have quickness, agility, and killing know-how (good finishing ability). Their powerful jaws and sharp claws make good weapons, and they are practiced at subduing animals larger than they are (usually cervids). Megalania will be tough to kill, but the Amur tiger should be quick enough to move into a favorable position to deliver a neck bite without receiving a bite itself on most occasions (but it will need to be careful). From a size perspective, this will be similar to a Komodo dragon taking on an Amur leopard. Both can win, but at these weights I give the edge to the tiger (assuming it is fit & healthy). Edge to Amur tiger.
3) 650kg Megalania vs 2x 150kg lioness: Lionesses are great hunters that use teamwork & strategy to ambush & overpower large prey items quite often. Animals that hunt in a group are often greater than the sum of their parts, but this Megalania is probably too big. Megalania has tough skin that will take time for the smaller cats to breach, and a bite from the giant lizard might be fatal. The quickness & agility of the lionesses will keep them relatively safe on most occasions, but the thrashing tail of the reptile will be a factor, and the felids may not care to invest the time needed to overpower this dangerous foe. The lionesses can succeed, but on most occasions Megalania will be able to stave them off. Edge to Megalania.
4) 100kg Komodo dragon vs 200kg wild boar: Komodo dragons are powerful reptiles with claws suited for effective digging, a whip-like tail, and a dangerous bite with sharp teeth used to tear flesh. It was once believed that the Komodo dragon's bite was effective in dispatching victims based solely on the presence of bacteria, but it is now known that the komodo also produces a toxin that can induce shock in its prey. It is also covered in bony scales that afford it protection from many attacks. Wild boars are aggressive mammals with sharp tusks and tough hides. They deal with a variety of perils in the form of predation from various carnivores, and can battle fiercely to defend themselves. Komodo dragons are great ambush predators, and one can certain overpower a wild boar (even a larger one) with the use of stealth. However, in a face-to-face encounter, the wild boar will have better lateral mobility and will be able to apply its offense with greater ease. The initial battle will certainly favor the wild boar (and it should be able to drive the smaller reptile away), but a solid bite from the komodo will spell doom for the suid. Wild boar wins.
5) 100kg Komodo dragon vs 80kg leopard: Leopards are among the strongest cats pound-for-pound, and occasionally drag large prey items into trees. They have typical felid attributes (speed, agility, athleticism, killing know-how), and regularly encounter dangerous adversaries (hyenas, baboons, etc.). Komodo dragons are the world's largest lizards, and are very capable predators. They have sharp teeth (1" long), toxic bites, whip-like tails, sharp claws, & tough hides (covered with small osteoderms). The leopard will have enough quickness (on most occasions) to avoid the komodo's bite and jump on its back, but may not be able to escape getting bit at some point during the struggle. The leopard should be able to subdue the Komodo dragon with its claws & teeth, but will eventually die if it receives a deep bite (the quick cat should have enough reaction time to keep this probability low). Leopard wins.
6) 18t Indricotherium vs 4x 600kg Utahraptor: Indricotherium was huge, and the one in this scenario weighs over 27 times as much as a single Utahraptor. Indricotherium's defense against predators was its great size, but it never had to encounter a predator as unique as Utahraptor. Utahraptors have decent bites, grabbing claws on their forelimbs, & kicking/slashing claws on their hindlimbs. They were also quick, agile, good leapers, & likely worked well as a team. The Utahraptors will have the ability to leap upon the Indricotherium, cling to it, and start biting & slashing without worry from an effective counter-attack. Indricotherium won't have the ability to stop this attack from happening because it won't be quick enough to apply any offense/defense that will subdue/repel the nimble theropods. From a size perspective, this will be like 4 Velociraptors (15kg) trying to subdue an animal the size of a zebra or a muskox. It will take a very long time, and they realistically might not bother with the attempt, but 4 determined Utahraptors will eventually cause enough damage & blood loss to subdue the Indricotherium. Overall, Utahraptors win.
7) 18t Indricotherium vs 5t Megatherium: Megatherium's hide was very tough, as a layer of tiny bony lumps created an armor just beneath the thick fur. Idricotherium didn't have to deal with adversaries once full-grown (except maybe others of its kind), and was likely a peaceful creature. A few swipes by Megatherium will probably drive the Indricotherium away, but a Indricotherium determined to attack the giant sloth will have the size to trample it (and Megatherium won't have the mobility to get out of the way). Being over 3 1/2 times as heavy in this scenario, Indricotherium will be too large for Megatherium to overpower if both animals are determined to engage (imagine a sloth bear trying to tangle with a dromedary camel or a grizzly bear trying to tangle with a giraffe). Indricotherium wins.
8) 18t Indricotherium vs 10.5t Triceratops: Triceratops was armed with 2 long brow horns and a neck frill that may have offered some protection for the anterior portion of its body. Triceratops occasionally jousted with rival males, and defended itself often from large theropods (like Tyrannosaurus). Indricotherium was likely peaceful, and used its great size to deter attackers. Among herbivores, the larger & more powerful animal usually gets its way in a typical setting, although this isn't always the case. In the same way a 3.5t rhino will give way to a 6t elephant, it is possible a Triceratops will yield (theoretically) to an Indricotherium if they both want to feed in the same area. However, it's unlikely an Indricotherium was nearly as aggressive as a bull elephant, and it certainly wasn't as well-armed as a Triceratops. Although Indricotherium may have been able to kick, bite, or even throw its weight around a bit to repel the Triceratops, no one knows its true combat ability. The Triceratops in this scenario will be about 2/3 the shoulder height of the Indricotherium, and its horns will be well-positioned to be plunged into the larger animal's side in a serious confrontation. Indricotherium will likely be driven away by the more combative Triceratops, and probably won't have the fortitude to fight back. Triceratops wins.