Tunnel

Tunnel Tier 1
variable mp reserve

opens two portals in two visible or familiar locations, joining them with this two-dimensional tunnel the two holes in reality create.

These portals are locked into place by some reference in space: either the same spot over the rotating crust of the Earth, someone's particular body part, an object in realspace, and so on.

These places are joined until a reference is too severely disrupted to maintain one or both portals, or until the user wills it.

Objects caught in the closing portal are harmlessly shunted to the side they "exist" on the most.

The distance between spaces, portal portability, and portal sizes determine their mana reserve cost: a general guideline is 10 + (10 per mile between) + (1 per inch wide).

Each portal that can be considered "mobile" (referenced to moveable objects) adds 50mp to the cost, and fizzles if either portal is ever taken beyond the maximum range initially set.

Though tunnel can use creatures as references, it cannot be opened inside of a creature.

This spell's maximums are 1 mile max and 10 inches wide per level.

Maximums are halved when using mobile portals.

Tunnel cannot be used to travel between dimensions or realities.

Tunnel Tier 2
Tunnel now has a permanent 20mp discount applied to its original formula for calculating mana cost.