My party better beware.   Having access online means no more floundering around for a a dinosaur in the book. Straight to battle with the right stats.  This would have eat my part if I could find it in the book on the fly.

nice

nicee

Not technically a dino >:(

still epic though :)

How is this CR 2? I mean, sure it could kill a first level party, but if a DM is having a first level party fight this, the DM is either really mean or really nice (by which I mean reducing the HP and damage of its attack). It's one of those two or the party is really, really good at the game. It doesn't quite make sense in my mind.

Well it's stronger than a cr1 monster. But it's not quite strong enough to be a cr3. Not all CR2 monsters are designed to be bosses for level 1 parties. Plenty can serve as one, but not all. I would use it as a puzzle-type encounter for a level 2, or maybe even level 3, party. It's stats portray it as an ambush predator, and it would be strange to use such a monster as a boss. Especially since it's aquatic.

Quote from Helmut_McQuack >>

How is this CR 2? I mean, sure it could kill a first level party, but if a DM is having a first level party fight this, the DM is either really mean or really nice (by which I mean reducing the HP and damage of its attack). It's one of those two or the party is really, really good at the game. It doesn't quite make sense in my mind.

Actually, I doubt very much a well-balanced lvl 1 party would lose to this (without considering animal friendship).

Let's consider a lvl 1 rogue, fighter, wizard and cleric.

Rogue: 9 hp, 15 ac, +5 to hit, 2d6+3 damage on hit (w/ sneak attack).
Fighter: 12 hp, 18 ac (chain+shield), +5 to hit, 1d8+5 damage on hit (w/dueling style).
Wizard: 7 hp, 15 ac (mage armor), on round one dealing 3d4+3, later +5 to hit, 1d8 damage (not using firebolt against an opponent submerged in water).
Cleric: 10 hp, 18 ac (chain + shield), +4 to hit, 1d6 +2 on hit, (or sacred flame [1d8, dex dc 13]). Let's assume both his 1st-level spell castings would be healing word.

Assume each character drops to 0 on a hit from dinodude (14 avg. damage).
Let's assume the fighter manages to take the aggro and is being attacked first.

Dino needs 12+ to hit fighter, so has 45% to hit. Dropping the fighter three times (since he'll get up twice with cleric's word) would take around 6 rounds.
On 6 rounds:
Wizard deals 10.5 on rnd 1, then has 65% to hit for 4.5 damage (avg). 0.65*4.5*5 rounds =14.625, +10.5, wizard will deal about 25 damage.
Rogue has 65% to deal 10 average damage (assuming either cleric or fighter stay near dino). That's 10*6.5*6 rounds=39 damage.
Fighter is harder to predict, since a lot depends on whether or not he comes after the cleric in initiative. Worst case he comes before, and misses his turns after dropping to 0. that means he'll get 3 attacks. 65% * 9.5 damage *3 rounds=18.5 damage.
Cleric - 60% to hit, 5.5 on hit, 6 rounds = around 20 damage.

That's 102 damage- waaaay more than than the dino's hp- before even the fighter is dead.

Sure, a true fight is much harder to predict, the dino might not just go for the fighter first, choose to dive after each attack, etc. And things'll get real bad if dino takes down the cleric or rolls a lethal crit. But overall, this (very shallow) analysis suggests a 1st level party should be able to handle a plesiosaurus.

I need about tree fiddy

True not technically a dinosaur. And in reality, it would not even attack the smallest characters because of their size. But it is still cool.

Daughter just used this in her first ever DM roll. The party was just 2 of us. Lv 3 Warlock, and Lv 3 Rouge. We had help from a Ch 3 Berserker Retired Pirate. We almost lost the Rouge, but managed to make it out okay.

one of my charcters tamed it and now its a mount as a dm im crying right now becuase shes a halfling and has a cap of water breathing

With conjure animals, I can summon these. There's no rule saying I can't spawn it in above my enemies, crushing them.

Quote from BlackMarketBob >>

With conjure animals, I can summon these. There's no rule saying I can't spawn it in above my enemies, crushing them.

 Conjure Animals doesn't let you choose where the fey beast(s) spawns.  It is only limited to a unoccupied space you can see.  So you would have to also limit where you can see to directly above your enemies.

https://www.dndbeyond.com/magic-items/7102434-prehistoric-figurine-of-wondrous-power-pyrite

LET'S GET READY TO RUMMM-BBBBLE

This will be fun to use with conjure animals

Obligatory word picture of a tortle paladin casting find greater steed and using this to crusade against merrow.

63-6R=57-12P=45-12P=33-4P=29-8P=21-9R=12-19R=0 

What?

Just fought this yesterday. Downed me in one shot.