The Muck is a sorcery speed High Tide that also costs just one
Chapter III in particular makes attacking feed you cards, so sometimes Shiva plays out like two turns of Moat. You can also try to combine this with other stun effects to draw extra cards, though there arent many of those (mostly just Ice Flan and Omega, Heartless Evolution)
It's an incredibly powerful card that has really helped boost Mono White in the format
While the obvious targets for Arena of Glorys exertion are creatures with powerful attack triggers like annihilator Eldrazi and Archon of Cruelty, anything with a ton of power looks much better when it speeds along like a Resilient Roadrunner
Once you meet the deckbuilding requirements, you get access to this powerhouse every single game
If you have any synergy with this, in the form of restricting resources or flickering Tax Collector, this can be really backbreaking