…they just fade away.
I had a Laser Optimus and this dragon toy who I had fight constantly. Its head and wings came off, so those made for some awesome fatalities, but he always regenerated. Optimus’ signature move was a sweeping uppercut.
One day, I had them fighting on a stack of giant blocks that was as tall as I was at the time, minus a bit. During the epic finale, Optimus punched the tower to make it fall on the dragon - despite the fact that it would land on him as well. But he’s Optimus Prime, god dammit. Self-sacrifice comes without a second thought.
After the rubble cleared, however, it was revealed that his left arm had broken off under the crushing strength of the tower… sad but not quite heartbroken, I chose to mark that as the final battle. Despite pleas to my father (I was technically inept at that age), the repairs were never gotten around to.
Over time, I grew older, and his battles became less infrequent. His trailer became lost to the sands of time and garage-boxes, his hips lost their strength (as this model is, apparently, infamous for doing) and until a few months ago I had forgotten that he ever had stickers. But still, every now and then, he fought new foes, still striking with his uppercut and, oftentimes, dealing crushing blows with his stub.
Pic related. Took it just now.
