It messes with utility creatures and forces opponents to tap their mana dorks and other activated abilities before their combat step if they dont want to toss them into the fray
This means they arent just useful in a giant-themed deck, but can often be found in a variety of different decks
While theres a lot to learn within Magic and comparing effects to their historical forebears, theres also much to learn by comparing Magic with its contemporaries
There are many more reasons beyond the mana difference why I would rather a Nihiri than a Pack Rat as a discard outlet in most situations
I came up with a very unique control deck that played into a really bizarre rules advantage of the time if you used Serrated Biskelions ability to give a creator a -1/-1 counter, you could phase out the Biskelion which meant your opponent received the counter, but your Biskelion wouldnt be there to weaken itself
The final tweak, was to create an instant that had a fluid customizability: This card is interesting because it encourages a player to build a deck with either a variety of creature types or with creatures that can change their creature type (see Mistforms above)