I dont like this quite as much as Aven Mindcensor because it isnt quite as devastating when it works sure, your opponent doesnt get their creature trigger, but they still get the creature, and most of the enters-the-battlefield triggers youre looking to stop (in Modern, anyway) are infinite combos that they can just try again once they find a removal spell for your one-toughness creature
Giratina has two distinct, massive forms, is over-designed in a good way, and its black, gray, red, and gold color palette is properly menacing
The most important of these is their -X ability
White used to be really bad, but honestly, it is kinda good now
haste A creature with haste can attack and you can activate its abilities as soon as it comes under your control
Instead of giving access to extra cards like Outpost Siege does, Uba Mask restricts cards that would be drawn to a use-it-or-lose-it existence in exile