The mysteries of octopus brains

A skewered baby octopus from a street stall - whole, soy-browned, and roasted just past tenderness - presented me with a few questions I'd never contemplated asking, let alone having answered:

1. Do cooked octopus brains taste, feel, and look exactly like hardboiled quail egg yolk?

I used to eat baby octopus salad all the time as a kid; my mom would bring a small container of it home from the seafood market as a special treat for me to eat for lunch.  But I never noticed that its brains tasted like egg yolk, so:

2. Alternatively, is it possible to somehow replace the brains of a seemingly intact baby octopus with the hardboiled yolk of a quail egg, fashioning the yolk as the brains and the white as the skull casing?  And if this is possible, would the Japanese actually do such a thing?

I think we can all agree that the answer to part 2 of question 2 is 'yes', but the practicalities involved in part 1 boggle the mind and would involve magical syringes at the very least.

But people build collapsible models of ships they slide into bottles and proceed to maneuver their sails up with string, so I'll accept the magical syringes.

Regardless, while trying to find my foodie footing in a country seemingly starved of street food (at least compared with its neighbors) it was refreshing to be able to exchange a skewer of something for a few coins and go along my merry market-wandering way with something mysterious in my mouth.