To Be Experimented on Is to Be This Type of Rodent
Puzzle 13 of Running a Marathon Pack
Question is: To Be Experimented on Is to Be This Type of Rodent
and the answer is: GUINEAPIG
Word Meaning:
GUINEA PIG — Any tailless rodent of the genus Cavia, which have short ears and superficially resemble large hamsters.
Definitions from Wiktionary.