The moment Graorin stands up the giant crab's attention switches to him and it moves towards you jerkily. At the same time the halflings leap up from their hiding place and charge directly at Old Claws, waving their spears and splashing through the shallows noisly.
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Roll maximum hit dice affected (2d4+1)[3] - Sorry!
Will save against Calm Animals (1d20+3)[8] DC14
The giant crab seems completely unaffected by your attempt to calm it, perhaps it is simply too hungry to care. The noises made by the halflings do distract it though and it swings its massive claws in their direction before circling to try to keep them and you in its sight. It is 30 feet from you when you release your spell, probably too far to get to you in the next round but still very close.
What are Devka and Athedru doing? Everyone else is unfortunately too far away even to hear the sounds of combat.