An Elethant wouldn't stand a chance... Triceratops would need to swing his skull one time, and no matter were he hits the elephant it would be an fatal strike which would lead to a certatin death 4 example by bleading, imobelizing and making the synapsid unable to live on..., or the destruction of vital organs...
Even if the Triceratops didnt had any horns he would still win because his bite was actually an deadlier weapon than the bite of all your favourite carnivorous theropod Dinosaurs (exept some Tyrannosaurs)
Yes Triceratops bite was stronger than the bite of Giganothosaurus, Spinosaurus, Carnotaurus, Acrocanthosaurus, Carchadonthosaurus... EVEN THOUGH HE WAS AN DAMN HERBIVORE!
Not only his jawpressure was monstrous his beak was a better close combat weapon than any of those above mentioned dinosaurs ever possesed, its robust shape and sharpe edges could easily crush bone and tear through flesh (better than the above mentioned theropods which are carnivorous) even though its was not made for this purpouse...
Not to mention his Archosaur scales, huge layers of flesh,fat muscle and bone (and eventually some thick scaleless skin on some parts) which would be an defense so strong an elephant wouldn't really be able to fataly destroy...
There is no way any species of elephant could win, triceratops would easily kill an full grown adult T-rex in the middle of the day!!!
The only reason Triceratops was ocasionally killed by T-rex was because he ambush attacked him when Triceratops cannot see well (which is during the night most likely when he sleeps) even though Triceratop's vision isn't as bad as they told you in old documentaries...
(Also T-rex hunted very likely in the middle of the night because T-rex's skull reveals structures around the eyes which are typical for nocturnal predators also the rest of his anatomy speaks for an ambush predator)
So when you ask yourself why Trex had such rediculously strong jawpressure and teeth, its because so he could effectivley, safetly take down an monstrous killing mashine at night when it cant see (and is probably sleeping) so that he dont get himself in a dangerous situation he would't be able to survive...
even running away wouldn't be 100% a way for T-rex to escape as Triceratops was quite a good runner for an quadruped Ceratopsian his size... (Triceratops had the speed around of an sprinting cuban crocodile)
So an Elephant would not be able to fataly injure or kill an Triceratops (because of his skin, archosaur scales, muscle fat and bone layers). But Triceratops would just need one hornswing to kill an elephant...
If his horns were bit of by a T-rex bevore the battle, triceratops would just need to bite the elephant in the leg or ribcage area to win the fight... The soft skined mammalian synapsid is an easy target here...
Voting for Triceratops for extremly obvious reasons...
From a logical scientific point of view this should be considered an ridicilous stomp...
(Sorry for my super bad English, tried to be as grammatically accurate as possebile)
