A riddle is a statement, question or phrase having a double or veiled meaning, put forth as a puzzle to be solved.

What does it mean to be riddled with something?

If an object is riddled with something, that means it's covered by that thing: for example, a tree trunk might be riddled with tiny holes made by the beaks of woodpeckers.

What does the word riddled?

Definition of fiddle (Entry 2 of 2) intransitive verb. 1 : to play on a fiddle. 2a : to move the hands or fingers restlessly. b : to spend time in aimless or fruitless activity : putter, tinker fiddled around with the engine for hours.