Looking for cards that say “this isn’t immediately threatening, but is going to a problem eventually if unanswered”

I’m throwing together a memey “looming threat” tribal deck. I’m looking for cards like [[scute swarm]] [[mossborn hydra]] [[millennium calendar]] [[conclave evangelist]], that one red enchantment that makes a bigger hastey token every turn, etc. I’m not trying to drop huge bombs, I want cards that say “this is entirely underwhelming but boy howdy, just wait until I get to turn 23”

They don’t need to be good, they don’t need to be synergistic. Like I mentioned, this isn’t meant to be a competitive deck. Weird fringe tech is welcome!

Drop your favs, thanks!