Ashcoat of the Shadow Swarm | Illustration by Christina Kraus Rat is a creature type in Magic that's been around since the very first set
Its real strength lies in being able to play artifacts from among the cards it exiles, giving them affinity as well, which can often result in playing colorless artifacts for free
When mixed with a card like Deadly Dispute (which Ichor Wellspring is the main target to sacrifice for Deadly Dispute's effect), you get to draw multiple cards to get a nice refresh of your hand while ramping
Toss in some flicker alongside this blue wizards spell recursion and you can set up some explosive turns
That nulls the effect of dying by sacrificing the aura instead, protecting your valuable creature
Broadly, there are two types of counterspells in Magic: hard and soft. Hard counters stop spells in their tracks without any restrictions, while soft spells either only stop the spell temporarily, or have an option to bypass the counter