When you transform into Guppy you get an effect similar to the Mulligan item: when you deal damage, there is some chance of a blue fly spawning. If I become Guppy and get the Mulligan, do they together have a higher chance of spawning blue flies than individually?

1 Answer 1


From Rebirth Wikia:

Isaac turns into his cat Guppy after picking up any three of the following items. In this form, Isaac gains flight and will produce blue flies every time an enemy is hit with a tear.

Otherwise, Mulligan "grants an infestation shot with a 1/6 chance of spawning allied blue flies when tears hit an enemy".

So in my opinion they can't stack, because being Guppy already grants a blue attack fly on each hit done.


I know we are talking about Rebirth, but in the previous version of the game, according to the original Wikia:

Once transformed, Isaac will gain flight and an enhanced version of The Mulligan, which always spawns Attack Flies when he or his familiars' tears strike an enemy.

If they could stack it would mean that you can spawn more than an attack fly, but as the old Wikia states, "you can't spawn two flies with one shot".

In the previous version of the game they didn't stack. And I have no evidence to think they have changed that.

  • 1
    Thanks for finding that information, but your conclusion doesn't necessarily follow. It could just as easily be that on each hit you get a guaranteed blue fly from Guppy and a 1/6 chance of getting another fly from the Mulligan. Commented Dec 22, 2014 at 22:32
  • In my opinion the Guppy transformation is un upgrade of Mulligan, that's why I don't think they could stack.
    – pinckerman
    Commented Dec 22, 2014 at 22:34
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    That's fine, but I'm looking for actual facts about how it works. Commented Dec 22, 2014 at 22:35
  • The previous wikia says that Guppy is an enhanced version of Mulligan, and different people say they don't stack, so I'm pretty sure of that.
    – pinckerman
    Commented Dec 22, 2014 at 22:43
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    The quote you just added also doesn't say that they don't stack, and it isn't relevant because mechanics have changed. Just provide one authoritative or researched source that actually says something about whether they stack and I'll accept the answer. Commented Dec 22, 2014 at 23:19

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