It provides Psychic Energy, and anytime the Pokemon is attached to is damaged, it puts 2 damage counters on the Attacking Pokemon (so long as it was the Active Pokemon) This may seem incredibly minor at first glance, but Pokemon is a game of inches
They can also send people hurling through time, which is put into the game via tucking creatures it would damage away into the library
This works with a variety of token producers like Anim Pakal, Thousandth Moon or Urabrask's Forge that either create tokens that enter tapped and attacking or create hasty tokens
Dack is a pretty good card when he has no synergy at all, he is great when he is fueling delve and such like
Exclusive in-game items for completing milestones
Using standard MTG sizing is important because it keeps cards compatible with sleeves, deck boxes, binders, playmats, and existing collections