Saber-Toothed Tiger

A friendly saber-toothed tiger is a beast companion or a ranger's bond. Plausible framings: a druid found the cub when its mother was killed by hunters and raised it from kitten size, a barbarian frost-clan reveres the saber-tooth and one chose this PC at the rite, a wizard has a Find Familiar variant that produced a juvenile saber-tooth instead of a cat. Run it as a beast companion: low Int, no language, but capable of being directed at a single target and trusted to commit.

In combat, the tiger is an opening-round assassin. With Stealth +7 and 50 ft. walk speed, it sets up by Hiding before initiative and pounces on round one for an attack with advantage from the unseen attacker rule. Use a Bite at roughly +6 for 2d10+4 piercing as the workable approximation, and call out the prone or grappled status if the party wants to rule a leap takes its target down. After the opening, AC 13 and 52 HP mean the tiger does not survive sustained attention from anything CR 3 or higher; pull it back after the first kill.

Out of combat, the tiger is a tracker and a deterrent. Passive Perception 15, Stealth +7, and darkvision 60 ft. make it the party's best scout in any wilderness or cave. It does not bark or growl unprompted, which means the rogue can finally walk through a forest without giving the camp away. The catch is meat: the tiger eats roughly its own body weight in a few days, and the party's rations are not enough. Have the player who handles the tiger track its hunting separately. The first time it kills a farmer's goat, there is a bill.

Name the tiger and let the player roll for its hunt every long rest. The party will protect it harder than they protect each other.

A saber-toothed tiger is an ambush predator with passive Perception 15 and Stealth +7, which means the party does not see it before it sees them. The stat block is sparse (no traits, no printed actions, just CR 2 statistics with darkvision 60 ft.), so you are running it as a hungry big cat: it stalks, it pounces, it bites. Treat the absence of a printed attack as a signal to keep things simple and use a Bite at roughly +6 for 2d10+4 piercing as the obvious read for a CR 2 large beast at the table. If your group prefers strict-as-printed, lean even harder on the stalk-and-pounce structure and let the speed and surprise do the work.

The opening turn is the entire encounter. Roll Stealth +7 against the party's passive Perceptions; with a 50 ft. walk speed and prehistoric ambush instincts, the tiger should usually win and trigger a surprise round. It charges from cover at the most isolated PC (the ranger who walked ahead, the wizard who fell behind), Hides if it can, then leaps on the kill. The tiger does not engage the fighter in the front line. It cuts one PC off, drags them, and disengages. If the party isn't watching their flanks, this is a one-PC fight per round.

These are unaligned beasts with Int 3. They do not flank, they do not coordinate with anything else (one tiger is the encounter, not a pack), and they do not understand magic. They do understand fire, loud noise, and pain. A torch in the face makes the tiger flinch back 10 ft. Thunder spells make it hesitate. A successful hit on it that rolls more than 15 damage is enough to make the cat consider whether this prey is worth dying for.

When the tiger is Bloodied (26 HP or less) it breaks contact, sprints 50 ft. into cover, and disappears. Do not let the party follow easily; Stealth +7 in undergrowth or a cave system is a very hard track. The tiger remembers the shape of the things that hurt it and avoids the party's camp for a week. Then it tries again, on a different PC, in a different place. A returning saber-tooth is a real recurring villain in a low-level wilderness arc.