[Gideon]

So I was rereading engulf and I have to question how Engulf works.

1) The critter must make a "Melee attack" to engulf a victim and the net hits add to the DV=critter's Magic.
-Question: Does the critter have to reroll the hitss every Action to maintain the level of damage per Action?  e.g. Magic 4 Water elemental, makes 3 net hits has a DV=7, next round is it 4, 7 or rerolled?  I ask because the power is sustained which means the critter does not have to take any action to keep something engulfed.

2) Can a critter move around after engulfing 1 or more victims?

Thanks, know its a nit-pick but has been bothering me as I prepare a Toxic Shaman mission tonight.

[Chaemera]

Every time the critter's Action Phase comes up, the critter automatically inflicts damage with a base DV equal to its Magic attribute. Net hits on the melee attack increase the DV of this damage. The victim resists this damage normally with a Damage Resistance Test, using Body + half Impact armor (round up_ unless otherwise noted.

Emphasis mine.

As you noted, the damage happens automatically, without effort on the critter's part. So he doesn't re-roll the damage every round. The damage is, as stated, Magic + Net Hits from the original melee attack. So it's 7S every round in your example (resisted with Body + half Impact).

Your second question is iffy-er. Officially, you have the following:

Engulfed victims may not move.

GM interpretation could go either way, nothing stops the engulfer from moving, but since the engulfee, per RAW, may not move, then the GM may read that as saying that if the engulfer moves, the engulfee is left behind.

Don't forget, the engulf power draws the victim into the critter or terrain it controls (SR4A, pg. 294, Engulf). So, you can drag the engulfee into a lake instead of the water elemental itself. Then he's stuck AND the spirit is clearly free to move.

[voydangel]

The Engulf power gives a critter the ability to draw victims into
itself or the terrain it controls, thus smothering the victim. Treat
Engulf as a melee attack. If the attack succeeds, it inflicts damage
(see below) and the critter engulfs the victim in its grasp. Every time
the critter’s Action Phase comes up, the critter automatically inflicts
damage with a base DV equal to its Magic attribute. Net hits on the
melee attack increase the DV of this damage. The victim resists this
damage normally with a Damage Resistance Test, using Body + half
Impact armor (round up) unless otherwise noted.

Emphasis mine.

1. The way I see it, the critter/spirit does not have to make any additional action to maintain the effect other than keeping it sustained. The victim would have to resist 7DV damage every time the critter got an action phase (based on your example question), the power is not rerolled each time, and the full DV of the initial attack is inflicted each and every time.

2. As I understand it, the engulf doesn't necessarily require the victim to be pulled into the spirit or critter itself as noted by the "or the terrain it controls" bit in the above paragraph. So, yes, the spirit or critter could move around all it wants after engulfing any number of victims. Also, it doesn't say anywhere that the spirit or critter can't move, so there's no reason to assume this is the case.

Good luck with your toxies  

Edit: beat me to the punch...

[FastJack]

Good job Padawans. You are learning the quick response well. I am glad I am able to watch some TV and you shall present the answers they seek.

[Gideon]

 thank you all 

this expains it well.  Question two's answer was critical to the run.

I have to confess that critters have been my weak point.

Making a conscious effort to include them more.