To find the mas, we use the kinetic energy definition
[tex]K=\frac{1}{2}mv^2[/tex]Where K = 3,168 Joules and v = 12 m/s.
[tex]\begin{gathered} 3,168J=\frac{1}{2}\cdot m\cdot(12m/s)^2 \\ 2\cdot3,168J=m\cdot144m^2/s^2 \\ \frac{6,336}{144}kg=m \\ m=44\operatorname{kg} \end{gathered}[/tex]Hence, the octopus' mass is 44 kilograms.