As agile as .... ???

Can somebody please complete the above for me?

Thanks, D

Agile as a cat.

Agile means "loose jointed" and "nimble footed," according to the This Dog'll Really Hunt: An Entertaining Texas Dictionary by Wallace O. Chariton (Wordware Publishing, Piano, Texas, 1989, 1990). A phrase from that book: "agile as a champion cuttin' horse."