ますきのこじゃなかったです
鱒茸じゃなかったです
masu kinokojanakattadesu

Noun
Desu Copula

The polite, past negative form of ますたけ

1. Wasn't mushroom.; Wasn't trout mushroom.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana