Conquest, the first horseman

Hexproof, Vigilance
When this creature enters the battlefield, tap all
opposing creatures, they do not untap
during the opponents next untap phase.
Whenever this creature deals damage, add
that many mana counters onto this card.
{t}: Remove all mana counters from this card.
Add that much black mana to your mana pool.
When this creature enters the battlefield, look at the top 10 cards of your library. Place the cards back on top of your library in any order.