My house-ruled oracle is considering taking as a spell known the complicated chain of perdition. The important part of the spell for this question is that the effect is a floating chain, and the caster can take a move action to "move the chain effect up to 30 feet," yet that appears to be the only way the chain can move.1 Nonetheless, the spell says the chain effect can use against a foe the combat maneuver drag, which says
If your attack is successful, both you and your target are moved 5 feet back, with your opponent occupying your original space and you in the space behind that in a straight line. For every 5 by which your attack exceeds your opponent's CMD, you can drag the target back an additional 5 feet. You must be able to move with the target to perform this maneuver. If you do not have enough movement, the drag goes to the maximum amount of movement available to you and ends.
Emphases mine. Is this a case of more specific trumping specific? (That is, success on the combat maneuver drag allows the chain to move anyway within the limits of the successful drag combat maneuver although the chain effect can't normally move.) Must the chain to drag a foe somehow be granted a movement speed? Is this just wrong and the chain effect can't really ever drag anything? Or is there something else about this spell I should know?
"Why off a cliff?": The combat maneuver reposition—which the chain effect can also perform and which doesn't carry any questionable baggage—forbids putting a "foe into a space that is intrinsically dangerous," while the combat maneuver drag doesn't have such a restriction. From a design standpoint, I think this is because when dragging a foe the attacker must first traverse the same spaces as the foe, which for most attackers would be unwise if one of those spaces is, for example, off a cliff. However, a magical nigh-invulnerable flying force chain often won't really care what spaces it goes through while dragging a dude.
1 Whether the caster's move action causes the chain effect to teleport to its new location or float conventionally (as conventionally as a magical floating chain of force can, anyway) to its new location isn't mentioned in the spell description. This makes me sad. But at least it can move at all; the spell's author says the chain effect's movement was added by the spell's editor.