Megalodonna

Noun. A fair and beautiful woman who, much like the megalodon shark, is larger than most of her kind.

Megalodon is to shark, as megalodonna is to belladonna.

Otis: You think Darcy will be at the party? I've wanted to hook up with her for a long time.

Gunther: Really? She weighs, like, three of you.

Otis: I know. Oh, how I long for my plump MEGALODONNA.