Walt Disney Wolrd
Harry Potter and the Deathly Hollows
The 2016 Summer Olympic games
James and the Giant Peach
United States of America
Night at the Museum
The legend of Sleepy Hallow
A simile is being used. Grendel is comparing "him" to a "fly" using like or as
I would say "Laurie’s lack of ambition" however I'm not too sure, hope it possibly helps.
Answer:
It compares the frozen crystals to delicately lacy snowflakes having an unexpected strength.
Explanation:
A Metaphor may be defined as a figure of speech where a phrase or a word is applied to an action or an object to which it can not literally or directly applicable.
In the excerpt that has been given in the question, there is a direct comparison made for the frozen crystals. They look very soft and fine when we look at them but they are hard substances in real. They seems like a deceitful foe to be friends to the city.