[Fugo watches, completely distracted from their former argument by the delicate and precise movements of the mantis, a spoonful of strawberry and mascarpone poised in the air.]

[He murmurs, appreciatively:] Sei bella...

[Ah, right. The dessert. Fugo takes his bite while he both puts the name and the facts Giorno has presented him with to memory and calls up the definition of deimatic display. He doesn't recite it immediately, instead taking time to make a second appreciative noise about the strawberries. They're very, very good.]

Deimatic display: any pattern of threatening or startling behavior. In this case, the subject is making itself seem larger and is displaying warning coloration.