Cheapest priced copy (Ikoria: Lair of Behemoths): $0.35 at Card Kingdom, near mint, their price list as of .
Pollywog Symbiote 
Creature — Frog · 1/3 · Uncommon · Ikoria: Lair of Behemoths · #63
Each creature spell you cast costs {1} less to cast if it has mutate.
Whenever you cast a creature spell, if it has mutate, draw a card, then discard a card.
Legal inCommanderPioneerModernLegacyVintage
Not legal inBrawlStandardPauper
2 printings · $0.35 to $2.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Ikoria: Lair of Behemoths | 63 | Uncommon | $0.35 | $0.49 |
| Ikoria: Lair of Behemoths (Babygodzilla, Ruin Reborn) | 372 | Uncommon | $2.99 | $2.49 |
5 rulings from Wizards of the Coast
- 17 April 2020Pollywog Symbiote’s first ability applies to creature spells you cast that have mutate even if you don’t cast them for their mutate cost. Similarly, its second ability triggers even if the creature spell with mutate was cast for a cost other than its mutate cost.
- 17 April 2020Effects that reduce the generic mana cost of a spell (such as that of Pollywog Symbiote) can’t reduce that spell’s colored mana requirements.
- 17 April 2020Players can cast spells and activate abilities after the triggered ability resolves but before the spell that caused it to trigger does.
- 17 April 2020You draw a card and discard a card all while Pollywog Symbiote’s ability is resolving. Nothing can happen between the two, and no player may choose to take actions.
- 17 April 2020An ability that triggers when a player casts a spell resolves before the spell that caused it to trigger. It resolves even if that spell is countered.