A violation of Show, Don't Tell when fleshing out a fictional tangible. Making a fictional something come to life is difficult. You only have so much Willing Suspension of Disbelief to work with, and you don't just want this thing to be believable - you want it to have the characteristics it needs to have for the story to work. You want this character to be brave, that knife to be sharp, this table over there to be sturdy, and this means going through a lot of trouble. Think of a situation where the thing can show its true colors, think of a way that this situation can naturally arise out of the plot, think of a believable way for the thing to act and finally show the way it is - -