Cheapest priced copy (Commander 2019): $0.49 at Card Kingdom, near mint, their price list as of .
Thought Sponge 
Creature — Sponge · 1/1 · Rare · Commander 2019 · #12
Flash
This creature enters with a number of +1/+1 counters on it equal to the greatest number of cards an opponent has drawn this turn.
When this creature dies, draw cards equal to its power.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
1 printing · $0.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2019 | 12 | Rare | $0.49 | — |
4 rulings from Wizards of the Coast
- 23 August 2019Thought Sponge gets its +1/+1 counters at the moment it enters the battlefield. There's not a time that it's on the battlefield before its replacement effect has applied.
- 23 August 2019Use Thought Sponge's power as it last existed on the battlefield to determine how many cards to draw for its last ability. If that number is negative, you neither draw nor discard cards.
- 23 August 2019Thought Sponge checks the total number of cards drawn by each opponent, not how many were drawn due to a single instruction.
- 23 August 2019Thought Sponge checks how many cards were drawn by opponents this turn, even opponents who have left the game. The greatest number drawn by a single opponent is how many +1/+1 counters it enters with.