  We probe the collective dynamics of a quantum degenerate Bose-Bose mixture of
Cs and $^{174}$Yb with attractive interspecies interactions. Specifically, we
excite vertical center of mass oscillations of the Cs condensate, and observe
significant damping for the Cs dipole mode, due to the rapid transfer of energy
to the larger Yb component, and the ensuing acoustic dissipation. Numerical
simulations based on coupled Gross-Pitaevskii equations provide excellent
agreement, and additionally reveal the possibility of late-time revivals
(beating) which are found to be highly sensitive to the Cs and Yb atom number
combinations. By further tuning the interaction strength of Cs using a broad
Feshbach resonance, we explore the stability of the degenerate mixture, and
observe collapse of the Cs condensate mediated by the attractive Cs-Yb
interaction when $a_{\mathrm{Cs}}<50 \, a_0$, well above the single-species
collapse threshold, in good agreement with simulations.
