Ok, so the dwarf is grappled and trapped in my body. I take that to mean that since I'm not committing any resources to the hold, technically, I ought to be able to move at full speed with anything engulfed in me. If not, then I simply don't get as far, but it's kind of vague in the first place.
To start, speed bonus remains up.
Opposed grapple checks to Pin the dwarf. If he gets pinned, the second grapple check is to damage him.
Grapple 1 (Pin):
1d20(9)+14=23Grapple 2 (Damage or 2nd Pin attempt):
1d20(8)+9=17Slam/Unarmed damage (if 2nd check succeeds for damage):
3d8(7,3,5)+4=19 damage
Acid damage (regardless of anything else):
3d6(1,4,5)=10 acid damage
The dwarf must also save vs. paralysis, Fort DC 18
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I then move toward the shadowy human looking for gear. If I get to move full speed, I attempt to engulf. If not, I'm simply an impending threat.
Finally, as a swift action, I change my boost from move speed to AC.