Strengthen Door

Strengthen Door is a runic spell that appears in Ultima Underworld I.

Spell Description
This enchantment magically spikes a door of the caster's choosing, making it difficult for hostile creatures to pass through it. Mages setting up camp in unexplored territory may find this spell of use when they do not wish to be ambushed while asleep.

Trivia

 * This spell is, essentially, pointless in the game.