Most unique upgrades in a metroivania you've played?

Like for me I'd say the chicken in guacamelee 2 and the bash in ori. Both of them completely change the way the game is played. (edit: another one I'll add isn't really an upgrade but a main feature, the cloud step in the messenger requires you to attack in order to use a second jump so you can technically never touch ground if you always have something to hit)