Parent is referring to GOAL/GOOL [1], Lisps that were developed internally at Naughty Dog for game scripting (the first iteration for the Crash Bandicoot series, the second on for the Jak & Daxter era. It is said that these were very powerful systems that could compile to some very mean PS1/PS2 assembly. If you read about how they had to optimize Crash Bandicoot to be able to give that "wow"-factor at their first E3, blazing past all other PS1 games and setting a new standard, you'll know what I mean.
There's a very interesting blog series about it [2].
[1]: http://en.wikipedia.org/wiki/Game_Oriented_Assembly_Lisp
[2]: http://all-things-andy-gavin.com/2011/02/02/making-crash-ban...