Professor McGonagall

Vera Verto - When Professor McGonagall enters, and at
the beginning of your upkeep, put a transfiguration counter on up to one target creature.

Creatures with transfiguration counters on them are Goblet artifacts, lose all other types, and loses all abilities.

If there are 3 or more nontoken Goblets on the battlefield, instants and sorceries you cast have demonstrate.