Ever had your cells' garbage disposal system turn against you? That's basically what's happening here! The meme brilliantly captures the molecular drama when ubiquitin (the cellular hitman) meets a malfunctioning enzyme.
Ubiquitin is this tiny protein that tags other proteins for destruction - it's literally the grim reaper of your cells. When it shows up and says "Death," it's not being dramatic - that's literally its job description! It marks damaged or unwanted proteins for degradation, keeping your cells tidy.
The panicked "What the hell are you?" reaction is exactly how I imagine proteins would respond if they could talk. That enzyme was just minding its business being dysfunctional when the cellular executioner showed up!