Croaker is a period-2oscillator component consisting of six rotor cells in the shape of a toad, with three of them being alive in each generation. Unlike the similar flutter, it cannot be supported exclusively by stator cells. However, it can be seen in oscillators such as Lei, in which two of them are supported by two banana sparks. Certain phoenix oscillators also contain croakers, stabilized by flutters and/or other croakers.
In other rules
A lone croaker can act as a photon in rules such as B2a3r/S.