T was surprisingly difficult, though not for lack of options. My players fought a tojanida while riding on its back, but that was more of a set piece, and that’s a different topic. They’ve fought several titans, but of the “_____ titan” varieties, not the vanilla Monster Manual titan. They fought the tarrasque, but it’s surprisingly underpowered in 4E. We wrote our own version of the troglodyte for the 4E version of Savage Species we never finished, but we didn’t play it. Trolls, treants, tigers, tieflings, thri-kreen, these all made it into campaigns, but I didn’t do anything interesting with them. The only T creature I’ve spun to my satisfaction wasn’t a fight at all. It was window dressing.
A tyrannosaurus is a one-trick pony, even more than the hezrou. It approaches a target, it bites them, it grapples, it swallows, GOTO 10. The specifics of that strategy depend on who you ask; Pathfinder uses a larger tyrannosaurus with significantly higher damage, AC, and Perception but fewer hit points and an easier-to-escape stomach than D&D’s version. Neither book spends any time describing the creature because there’s nothing to say. If you don’t know what a tyrannosaurus is, you’re probably not interested in the stats for dinosaurs.
Truth be told, I don’t really like the tyrannosaurus. It’s normally too blunt for me, and I have a hard time having a dinosaur show up like a villain airlifted one in. I’m more likely to reskin it as anything with a single huge attack, especially one that can incapacitate a player for a while (take a drink). But for various reasons my players have fought several tyrannosauruses over the years. They sit at a good CR for me, at a level where the party is powerful but not “scry, teleport, coup de grâce” powerful. They’re easy to run and they usually strike fear in players’ hearts. The first huge-sized miniature I ever got was a fiendish tyrannosaurus, and I lean toward monsters I can represent on a table. And a tyrannosaur was responsible for one of my early player deaths, when he decided to climb down the creature’s throat to attack it from the inside but did not count on taking bite damage every round while the dinosaur was perfectly happy swallowing at its own pace, thank you very much. I do like monsters with player history attached.
But all of those were blunt applications for a blunt object. You don’t get to take credit for innovation by using a tool as intended. Rather, the instance I’m proud of happened in the first Eight Arms campaign, which took place mostly in the party’s home city. That city had a park, and inside that park lived a druid nicknamed Crazy Eddie. He was a legal resident of the city and by law technically could not be forced to vacate the park due to outstanding statutes only he remembered. He stood against modernization and wanted to preserve the last bit of relatively natural land in and around the city. Normally nobody would care, but in Pathfinder druids could have a tyrannosaurus as their animal companion, and as it turns out a giant dinosaur is an excellent deterrent to crime and government overreach.
Animal companion tyrannosauruses can normally only grow to large size, but I could not bring myself to care. In Pathfinder tyrannosauruses are normally gargantuan, so if they can be both size categories, they can also be the one in between. This let me use my mini again, so everybody was happy.
The players loved Crazy Eddie and his companion, and I think that’s mostly because he hated dealing with their characters and my players make an effort to inject frustration and entropy into every social system they come across. He and his tyrannosaurus made an appearance in the final city-wide battle, effectively defending the park from invaders by themselves, and the next time we have a campaign set in that city I’m going out of my way to make sure he shows up. Whether he is an ally or an enemy will depend on what the campaign is about and how likely the party is to be scared of a dinosaur in combat.