Sentence:  P-O-O-K-A. <WSD>Pooka</WSD>. From old Celtic mythology, a fairy spirit in animal form, always very large. The pooka appears here and there, now and then, to this one and that one. A benign but mischievous creature. Very fond of rumpots, crackpots, and how are you, Mr. Wilson? 
Meaning of the word marked with <WSD> tags:  A fairy that supposedly appears in animal form, often large.