DnD Spells: Gate

"Jagreen Lern has succeeded in making a sizable breach in the Law-constructed barrier which has hitherto kept the creatures of Chaos from wholly ruling our planet.  He is forever widening this breach as his power increases.  This explains how he could summon such a mighty assembly of Hell's nobility where, in the past, it was hard to bring even one of the Dukes of Hell to our plane."

-- Michael Moorcock, "Stormbringer"

Few of the DnD campaigns that I participated in ever reached the player character levels necessary to access ninth level magic-user spells.  One of those spells, Gate, permits the magic-user to open a gate to another plane and entreat a powerful entity to come to the caster's aid.

I've always wanted to include scrolls with spells like this, as treasure.  To have a powerful one-shot item that the players could use, in this case, to gate in a powerful entity, would be handy for those occasions where the party is overmatched and otherwise needs some deus-ex-machina intervention by the DM to survive.

The problem is that a lower-level magic user are more apt to write the spell into their spell-book (for use when they reach the necessary level) as keep the scroll as a one-use item, thus defeating the point of scrolls as one-shot magic items.