In particular, copying Terror of the Peaks or Savage Ventmaw with Miirym sounds amazing
Otherwise, draw a card. This might not sound like much at first glance, but then again neither does the zero-mana Kobold Rograkh, Son of Rohgahh, and look at how far that card has come (more on him in a bit)
(Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)
For example, Segovian Leviathan is a $3 uncommon from Legends , but this BGS 9.5 copy sold on eBay for $219.99
oldskoolpokemon February 19, 2020, 5:35am 12 That Pikachu looks Familiar Either that, or you have 2 of those back-stamped Pikachu Cards
Forcing everyone at the table to pay an additional three generic mana for each card they cast is absolutely back breaking and is sure to delay everyone's turns by a significant amount