Grandma's Secret Tonic
Grandma's Secret Tonic
Epic
Crits have a 50%chance to explode and damage nearby enemies for 50% damage.

Grandma's Secret Tonic Megabonk – Explained

Grandma's Secret Tonic gives your critical hits a chance to create an explosion that damages nearby enemies. It also provides a bonus to your crit chance.
 
The explosion is a pink explosion that looks like this Pasted image 
 
How it works:
 
- When you land a critical hit, Grandma's Secret Tonic has a 50% chance to trigger an explosion
- The explosion occurs at the hit enemy's position
- All enemies within the explosion radius take damage
- The explosion damage is 50% of the crit damage that triggered it
 
Crit chance bonus:
 
The first copy of Grandma's Secret Tonic you pick up gives you a +2% crit chance. This is ONLY for the first copy though
 
Explosion damage formula:
 
 
$$ \text{ExplosionDamage} = 0.5 \times \text{CritDamage} $$
 
 
Where CritDamage is the damage dealt by the critical hit that triggered the explosion.
 
Explosion radius formula:
 
 
$$ \text{Radius}(n, S) = \min\left(\max\left((3 + n) \times S,\ 1.0\right),\ 8.0\right) $$
 
 
Where
- $ n $ = number of Grandma's Secret Tonic copies
- $ S $ = your size stat multiplier
- Radius is clamped between 1.0 (minimum) and 8.0 (maximum)
 
Examples at different sizes:
 
 
CopiesSize 1.0xSize 1.5xSize 2.0x
14.06.08.0 (capped)
25.07.58.0 (capped)
36.08.0 (capped)8.0 (capped)
58.0 (capped)8.0 (capped)8.0 (capped)
Note that size is only calculated on pickup (or when the amount changes, for instance when getting less from microwaving it.)
This could lead to a funny scenario where if you picked up 2x tonic while your size was 1.0x, and later get 2.0x size and then microwave away 1 of your grandmas tonic, it actually becomes more powerful than if you had 2.

How it Stacks

1. Explosion Radius (Size-Dependent Linear Scaling)

 
The explosion radius scales with both copies and your size stat:
 
 
$$ \text{Radius}(n, S) = (3 + n) \times S $$
 
 
Where
- $ n $ = number of Grandma's Secret Tonic copies
- $ S $ = your size stat multiplier
 
Radius limits:
 
- Minimum radius: 1.0 (even if calculation is lower)
- Maximum radius: 8.0 (even if calculation is higher)
 
Examples at different sizes:
 
 
CopiesSize 1.0xSize 1.5xSize 2.0x
14.06.08.0 (capped)
25.07.58.0 (capped)
36.08.0 (capped)8.0 (capped)
58.0 (capped)8.0 (capped)8.0 (capped)

Important note on size

It only calculates size on pickup. So if you pickup 1 grandmas tonic at 1.0x size and later get 2.0x size, the radius will not get increased. But when you pick up your second copy it will re-calculate how much the size multiplier should impact the stat. So if you pickup the 2nd copy at 2.0x size you will have reached the max cap for this item.
 

3. Fixed Values

 
These values do not change with more copies:
 
- Proc chance: Always 50% (does not scale)
- Explosion damage multiplier: Always 50% of crit damage (does not scale)
 

Approved suggestions and replies (if you left feedback and it is approved your comment will show up here).

  • BobFeb 26, 2026
    Grandma's Secret Tonic: On the left it says: Damage determined by: Amount of Grandma's Secret Tonics On the right it says: Explosion damage multiplier: Always 50% of crit damage (does not scale) These two pieces of info seem to be in conflict? Thanks
    Reply from IndieSnek:
    oh yeah you're right, thank you for pointing that out! Damage does indeed NOT scale with more grandmas tonic. Typo error