Was Improved Grab modified during system revision?

Question

Is the Improved Grab ability different in 3.0? Like, I don't know, maybe no special size restriction, or it working like the 3.5 version's -20 without an actual -20 penalty?

For reference, the question comes from the Gibbering Mouther and its change in the 3.5 MM errata. It seems it doesn't work well before the errata, but it also seems it may actually be the fault of insufficient change (or lack of sufficient change) of the monster during system revision.

I just don't get how a Gibbering Mouther can manage to have a single "opponent grabbed by three or more mouths", or by more than a single mouth at all, for that matter.

Answer 1

Yes, there is a difference.

For reference: 3.0 SRD text file on Special Abilities and 3.5 hypertext SRD for Improved Grab

The first paragraph of the 3.0 ability reads:

If the creature hits with a melee weapon (usually a claw or bite attack), it deals normal damage and attempts to start a grapple as a free action without provoking an attack of opportunity. No initial touch attack is required, and Tiny and Small creatures do not suffer a special size penalty.

This text is removed in the 3.5 version of the ability. However, the Mouther is Medium, so that is irrelevant in your case. Both versions include this size-related text:

Unless otherwise stated, improved grab works only against opponents at least one size category smaller than the creature.

As a Medium monster, the Mouther can only use its Improved Grab on small creatures, even in 3.0.

The -20 functionality is identical across versions - the creature can take a -20 penalty to use only one body part and avoid suffering the consequences of a grapple, or deal with the loss of mobility and DEX to AC.