At the start of each end step, you get to make 1/1 Rat tokens that are effectively Relentless Rats equal to the number of creatures your opponents control that were exiled that turn
Against the creature decks, this card is pretty uninspiring as a defensive body, and it faces the same issues of not being able to attack well that Merfolk Trickster can struggle with
And, if those creatures dont survive in the long run, you can eventually use the Equipment cards (that stick around) to close out the game
Whenever you use a Clue (read: spend 2 mana to sacrifice the token and draw a card), you venture into the dungeon
Undercity This dungeon features options to scry, draw, or tutor from your top ten cards directly into play
However, I can think of 2 situations that this card would add immense value (and theres likely even more): When youre playing a team game and have excess mana available to help untap a teammates lands