Flashover- I was about to say what happened! It shrunk and has fork boots now-then I noticed the Grey Mare.
The guys last into the engine likely used Hondabond/Yamabond, XXXXXbond, that clay/solventbased sticky, pain in the arse to clean up stuff.
Patience, time, and a non-marring scraper to get it off are all your friends.
No, really, the mustache means I love you.