If you're already in the Undercity dungeon, then cards that read venture into the dungeon will instead progress you to the next room in the Undercity as opposed to having you enter another dungeon
Every player starts with 40 HP and when someone is hit by a non-commander creature, you subtract from this pool
(2021-06-18) If you pay the dash cost to cast a creature spell, that card will be returned to its owner's hand only if it's still on the battlefield when its triggered ability resolves
Those are definitely corner cases though, and Flickerwisp does its best work flickering a permanent for enter the battlefield value
Using its [Trigger], you can play a Character with a cost of 4 or less, such as "OP14-111 Perona" or "OP14-109 Victoria Cindry," from your trash, which lets you catch your opponent off-guard and reduce their options at unexpected times