If you somehow control Battle of Hoover Dam and no choice was made for it (perhaps because another permanent on the battlefield became a copy of it), it has neither of the two triggered abilities
Cards that would go to your graveyard still will, even while your graveyard is a creature on the battlefield
In the case of Time Walk, it retained its devastating ability: take an extra turn for just two manaone of the strongest effects in the entire MTG game
Its attack, Psy Purge , is nice thanks to its versatility by simple two psychic energies, and can be accelerated easily between turns or Pokmon that support it, such as Cresselia CRE 64 or Shadow Rider Calyrex VMAX CRE 75, it can discard up to 3 Energy from your Pokmon, which is 90 damage for each Energy discarded in the process
Whether youre hiding tokens in your sleeves, under land, or even under your opponents creatures, Surprise Party is always a good time
Whats so crazy about it is that you dont have to put those, say, eight -1/-1 counters on your 8 toughness creature