Are monojets due to unusual Z0 decays?

We examine and compare implications of several recent suggestions that events of the form $\text{p}\text{p}\text{→}\text{jet}\text{+(}\text{missing transverse momentum}\text{)}$ could be due to unusual Z⁰ decays. Two possibilities are noted: (a) $\text{Z}{}^0\text{→}\text{N}\text{N}$, where N (or $\text{N}$) is a neutral heavy lepton decaying to three neutrinos with a 10% branching ratio, and (b) Z⁰→h₁h₂, where h₁ and h₂ are two distinct spinless particles, and only the decay of h₁ is seen in the detector. Early tests of both possibilities are noted.