The perfect opportunity arose for my players to encounter a dire crocodile, but as I have been preparing for the encounter, I have been a bit confused as to how to interpret the death roll rules.
The dire crocodile in pathfinder has two special attacks: death roll, and swallow whole. The wording on death roll makes me believe that it would make a bite attack, grab, death roll (having rolled a successful grapple check) in the first round of combat, assuming of course that everything was successful.
Grab: If a creature with this special attack hits with the indicated attack (bite), it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity. The creature has the option to conduct the grapple normally or simply to use the part of its body it used in the grab to hold the opponent…
Then
Death Roll: When grappling a foe of its size or smaller, a crocodile can perform a death roll upon making a successful grapple check. As it clings to its foe, it tucks in its legs and rolls rapidly, twisting and wrenching its victim. The crocodile inflicts its bite damage and knocks the creature prone. If successful, the crocodile maintains its grapple.
Now, the reason I believe that the dire crocodile would be able to death roll on that opening attack is because of how clearly the swallow whole ability is written…
Relevant section from swallow whole: If a creature with this special attack begins its turn with an opponent grappled in its mouth (see grab), it can attempt a new combat maneuver check (as though attempting to pin its opponent). If it succeeds, it swallows its prey and the opponent takes bite damage…
So with swallow whole, I would interpret that as a second opportunity to death roll (because of a successful grapple check) before being swallowed.
Best Answer
The Death Roll ability is not a triggered ability; the crocodile merely gains the option to use it once it has a foe grappled.
The "upon making a successful grapple check" is essentially the action the crocodile is taking to execute the death roll.
In other words: If the crocodile already has a creature of its size of smaller grappled, it make decide to perform a Death Roll as an action. It then will roll a grapple check and if it succeeds, it deals damage, etc.