It doesn't have to be your own character, either
The people expecting Xenagos to stay at $40 were betting on a two-color planeswalker being so good that it would see play as a four-of in multiple tier 1 decks, which never seemed likely to me
This blue and white Standard MTG deck has no creatures in the main list
It's a fantastic way to close out the game in EDH, too, jumping your whole team, repeatedly if need be
Hydroid Krasis is probably the biggest offender out of all of those
The deck features 3 copies of Yorvo, Lord of Garenbrig, which is already a very strong creature at 4/4 for 3 mana, but also gets stronger each time you cast a green creature (and all your creatures are green!) The deck adds 3 copies of Thunderous snapper, which is already a 4/4 for 4 mana, but also draws you cards each time you cast big creatures