The Sims 4: Grim's Ghoulish Guitar

The Sims 4: Grim's Ghoulish Guitar is a free DLC pack for The Sims 4. It was announced by SimGuruDrake on August 18, 2016.* The player needs to sign up for emails about The Sims to get the pack.

Official description
'Is your Sim musically inclined? Can they rock out? Have they been known to shred on occasion? If so, they'll definitely want to add this axe to their collection. It's Grim's Ghoulish Guitar, and it's exclusively available to those who sign up for The Sims 4 newsletter. The guitar's eyes glow, and a cloud of black smoke will appear under your Sim - just like Grim. It's rockin'!'