Alright. Let's settle this Carbuncle thing once and for all with a good old pros and cons:

Cons:

1. It's understatted for a 4 drop
2. If you use too many in a game it can get annoying for draws
3. You might possibly not draw one of the spells before turn 9-10? I guess? Not really a con since that applies to literally every card in the game and to a greater extent but people mention it so let's throw that in.
4. You might possibly draw a sparkle instead of X drop you need and then be unable to play it because you spent 1pp that you needed? Sure. I guess less...errr..."topdeck reliability?" is a problem? But then you're also more likely to be playing cards like Metera when you otherwise couldn't so maybe that balances out anyway getting extra card draw and immediate tempo swings.
5. Despite largely behaving like a 2 drop it can't be considered one, taking up a 4 drop slot instead.

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Pros

1. It can recover pp on evo to negate the tempo loss of its small body relative to cost
2. It has an evo effect to restore 2 defense
3. Gives you late game sustainability
4. Makes powerful evo reliant followers like Metera useful even in the late game since you'll have extra evos
5. Allows you to evo Yggdrasil instead of using Wrath on her in the late game. Meaning you could give rush to something else (Bayle? Eve?) or save Wrath for a rainy day. Similar to the previous point but distinct enough to warrant its own point.
6. Provides extra healing with the spells
7. Spells can be used to help proc "cards played" effects efficiently and without reducing handsize or taking up board space.
8. "Do nothing" cards with otherwise powerful effects can become more playable with additional evos.
9. Can help you reach lethal with additional evos used aggressively.
10. Spells are tutorable.
11. Is cute.

I think the card is bonkers good. Possibly too good to not run except in the absolute most aggressive decks and even then the extra evos can help. Make up your own mind though.