Mysterious — difficult to understand or explain; strange
Lightning strike — an incident in which lightning hits somebody/something
Tax — money that you have to pay to the government so that it can pay for public services. People pay tax according to their income and businesses pay tax according to their profits. Tax is also often paid on goods and services.
Scent — the pleasant smell that something has
Chronic — lasting for a long time; difficult to cure
Cough — an act or a sound of coughing (= forcing out air suddenly and noisily through your throat, for example when you have a cold)
Octopus — a sea creature with a soft round body and eight long arms, that is sometimes used for food
Definition of mysterious from the Oxford Advanced Learner's Dictionary[