also: アヴァンタイトル
noun
pre-credits sequence; cold open; opening scene before credits
Refers to the segment of a film, TV show, or anime that plays before the opening credits or title sequence. Often used to hook the audience.
from French avant · from English title
この映画のアバンタイトルはとても印象的だった。
The pre-credits sequence of this movie was very impressive.
アニメのアバンタイトルでいきなりクライマックスを見
There is a technique of showing the climax right away in the cold open of an anime.