This will hopefully get nerfed quickly after I post, but there is a very lethal and very annoying two-card combo using only rare cards for a total of 16 mana. The rest of the deck can be enhanced around it, but it uses just Sharp-Eyed Rookie from MKM and Pinnacle Emissary from EOE.
It does require a turn to attack unless you also have haste and/or trample, but at 16 total mana it’s lightning-quick. Sequencing doesn’t matter, both of these cards trigger themselves upon entering which in turn triggers the other when on the battlefield. It generates not just a huge stack of robot tokens but also a very heavily buffed Rookie, so there are two huge threats to deal with. The bonus that makes it tougher to combat is that each trigger generates a clue token, which spawns a robot, which generates a clue token, etc until the board is completely full. This means unless you have a board wipe handy, you’re stuck only with the mana gained from your next swap because there’s no direct way to convert gems. And even if you board wipe and get rid of the creatures, destroying the clues means the opponent has a full hand to start all over again.
I’d argue this is a bigger short-term problem than Ocelot - total cost is cheaper, rarity/set is more accessible, doesn’t require sequencing or another external trigger, and using the second ability of Domri1 gets it accomplished almost immediately in most cases. Because Greg prioritizes creatures it’s easy to run into. And worst of all you have to sit through all the trigger animations until the board is full and the buffs complete.
I realize the nerf will probably be to limit the number of times one of these two cards triggers, but want to get attention on it before the next patch if possible.