Dome of Defense

Prerequisite: A variant of Tiny Hut for those whose background or faith includes the idea of wards to protect your allies and/or frustrate your enemies. It is also more detailed and specific in its effects.

As the final part of the spell is cast, a shimmering bubble of force expands out from the caster until it has reached either the maximum distance as specified by the caster or 10', whichever is smaller.  The minimum size it can be cast at is a 5' radius. It will pass thru anything inside its radius until it reaches its intended size at which point it solidifies into an up to a 10-foot-radius ellipsoidal dome of force locked to the surface under it with a 1" flat surface of force that those inside will find themselves standing or sitting on.  Soft surfaces such as dirt will be pressed down if possible. Once successfully cast, the dome will remain stationary, relative to the surface for the duration, locked to a circular pattern of softly glowing runes around the inside border. Thus a dome cast on the surface of a large ship would move with it, but if cast on a rowboat, it would fail as the surface for it isn't large enough.

The spell fails if:

• The area at time of casting includes a larger creature or more than nine creatures of small size or above. So a swarm of bats won't cause the spell to fail, but 5 mages with 5 donkeys will.
• The dome is too large for the area it is cast into . Thus a 5' radius dome could fit into a 10x10 room, but a 10' radius dome couldn't and would fail if cast.
• The creatures and objects inside at casting are positioned such that more than 100 lbs of force would be required to move them totally inside the dome. Thus an 8' tall ogre standing next to the caster would be fine, but if the same ogre was at the border of the spell and resisted being pushed inside by the spell during its final phase, it would fail.  

Once successfully cast:

• A vertical cross section of the dome is an ellipse specified by the caster ranging from a quarter sphere (height = 1/2 radius) to a hemisphere (height = radius) to an elongated dome (height = diameter). 
• Up to nine creatures of Medium size or smaller can fit inside the dome with you, although if the dome is too small this number may be reduced by the GM. Tiny creatures which are not magically bonded or magical in themselves, like a swarm of bats or insects, don't count against this limit. But familiars and pixies, for example, would. A non magical pet bird like a canary, however, would not.
• Creatures and objects within the dome when you cast this spell can move through it freely. All other creatures and objects are barred from passing through it.
• Spells and other magical effects can't extend through the dome or be cast through it. However magical items such as armor and swords, which were inside at the time of casting can pass thru it if carried by one of the people allowed to pass.
• Spells can be cast inside the dome, but their effects will not pass thru it. Thus if the caster's familiar leaves the dome, telepathic communication to it is blocked by the dome while it is outside since that is a magical effect. Similarly an echo knight's echo can not pass thru the dome. 
• Items not carried by a person inside the dome will not pass thru it. So you can't shoot arrows or toss rocks out of the dome, but you can step outside carrying them and then shoot them.
• Non magical small objects such as coins, gems, buckets of water, wine bottles, rocks or arrows picked up outside by those allowed to pass may be carried inside. Large objects, magical items, spell books, scrolls and the like which were not inside at casting may not and will bounce off the outer shell of the dome if someone tries it.  
• The atmosphere inside the space is comfortable, breathable and dry, regardless of the weather outside. Thus rain and clouds of magical gas will not pass thru it. 
• Until the spell ends, you can command the interior to become dimly lit or dark.
• The dome is usually opaque from the outside, of any color you choose, but it is transparent from the inside. It may be made almost transparent from the outside, but a DC 10 perception roll will spot the tell-tale shimmer.
• As the dome has a floor, tunneling creatures may not bypass its defenses by coming thru it. 

The dome may be destroyed as follows:

• The caster leaves its area
• Time expires.
• A dispel magic cast at a level equal or higher than the dome will bring it down. This if the dome was cast using a 5th level slot, then a dispel magic would also need to be cast using a slot of 5th level or above to bring it down.
• Disintegrate ray or spell
• Anti-magic spell.
• Limited wish, wish or equivalent spell or ability
• Ironically a sphere of annihilation will not pass thru it or destroy it, but merely roll around its perimeter making this one of the few defenses against such. Note, however that no one in the dome can attempt to control such a sphere.