Belgafor, Grixis's First Bane

Belgafor, Grixis's First Bane can't be countered.
Reach, trample
When Belgafor, Grixis's First Bane enters the battlefield, each opponent discards a card at random, then sacrifices X permanents, where
X is equal to that card's converted mana cost.
Creatures with power lesser than its toughness
can't attack or block.