  We construct an explicit example of a generalized Lie 3-algebra from the
octonions. In combination with the result of arXiv:0807.0808, this gives rise
to a three-dimensional N=2 Chern-Simons-matter theory with exceptional gauge
group G_2 and with global symmetry SU(4)\times U(1). This gives a possible
candidate for the theory on multiple M2-branes with G_2 gauge symmetry.
