That means you could wait three turns to remove those counters, and then the spell triggers
If the target of Fear of Lost Teeth's ability is an illegal target as the ability tries to resolve, it won't resolve and none of its effects will happen
That extra hoop isnt a big problem when presented on cards like Azorius Signet, as you can turn colorless mana into colored mana with the added benefit of skipping summoning sickness
In particular, the Counter Intelligence deck seems to be continuing to impress as its now causing fresh price spikes
However, if you choose any targets for the ability and each of them becomes an illegal target, the ability doesn't resolve and you don't create any tokens
Then, at any point in the game, that player can pay the mana cost of that card, and turn it face up on the battlefield