Sanguijuela cerebral

Jorbs

One hidden element of this event is that you're allowed to skip the Colorless card reward, but forced to take a card if you choose 1 of 5 random cards (which come from your character's card pool). Because of this, it can be a little more appealing to look at Colorless cards, as long as you won't put yourself in immediate danger by paying the health. There are some very fun Colorless cards you can get early in the run this way. One of my favorites is Fasten, which lets basic defends remain strong throughout the entire run. Looking at five cards from your character's card pool isn't bad either, though!

Baalorlord

Colorless cards tend to be slightly stronger than regular cards, so option 2 is my default here unless I can't afford the health loss. There's a good number of Power cards in the colorless pool which can give you quite a boost. Choosing from 5 regular cards can be worth it if you're trying to get a particular build going.