mtg arena card draw 15 Best Black Cards in MTG! Commander Clash Podcast 061: Card

Its not necessarily about attacking that player, but they get dinged anyway

Prime Minister's Cabinet Room Plane Earth At the beginning of combat on your turn, up to one target creature you control becomes a copy of target creature an opponent controls

Notably, you can use this to fetch Tiamat and Omniscience

The downside is that the lands now enter the battlefield tapped so you don't get to use them immediately and Roiling Regrowth is worse to copy than Harrow, since Reverberate'ing Harrow nets you 2 extra lands while copying Roiling Regrowth only nets you 1 extra land

Merged creatures have all the abilities of every creature in the pile as well as the combat stats and creature type of the topmost creature

Activated abilities require you to pay a cost and choose when to use them