B-heptomino

Perturbations of its reaction also reproduce it in different generations. This might be tamed someday to form glider guns or puffers, as the B-heptomino in Life has been.

Source: wiktionary

Actually, the period 30 "queen bee" shuttle seems irreparable, as it contains several instances of the Ship neighborhood duriod its cycle. It's the period 46 b-heptomino shuttle that can be stabilized with clocks.

Source: wiktionary

In B37/S23, it goes symmetrical after 10 ticks, and produces a familiar pair of B-heptominoes after 23 ticks (the next generation after this can be found in the rotor of a standard B3/S23 p46 oscillator):

Source: wiktionary