D&D 3.5: Monster Reach and Size Category Changes

[InterstellarPro]

What happens when a creature with an abnormal reach grows in size? For instance, if I were to create an advanced roper to throw at my party, and I advanced it to 16+ HD, it would grow to 15 ft. space and 15 ft. reach with its bite attack, but its tendrils have a 50 ft. reach when the roper is Large. Does that reach remain the same? Increase by 5 ft.? Or increase by whatever I want since it is my advanced monster?

Link to Roper:
http://www.d20srd.org/srd/monsters/roper.htm

Another possibility: since the creature's general reach increases 50%, maybe its tendrils might do the same, increasing to 75 ft. reach.

[Jowgen]

To throw atop this query, there is also the matter of things like the Warshaper's extra reach ability, or those reach weapons that have 15 ft reach at medium (e.g. rope dart, tentacle whip).

Any kinda answer to OP that also covers these sorts of scenarios would be most appreciated.

[FelineArchmage]

Not sure how it would work by RAW, but perhaps it can be resolved by keeping the size category to reach to tendril the same when increasing in size?

[Khedrac]

Basically any unusual reach for a creature becomes "DM's Call" when the creature is enlarged.

One cannot even look at octopus and giant octopus for an example because the octopus just has 5' reach (same for the squid).

[martixy]

I don't believe this is addressed anywhere explicitly.

However, we could extrapolate from prior data.

I have only ever seen exactly ONE instance where reach has worked multiplicatively - reach weapons. In all other instances, it's always been additive. Meaning your roper would now have +5 ft reach with his tendrils, for a total of 55 ft.

[InterstellarPro]

I don't believe this is addressed anywhere explicitly.

However, we could extrapolate from prior data.

I have only ever seen exactly ONE instance where reach has worked multiplicatively - reach weapons. In all other instances, it's always been additive. Meaning your roper would now have +5 ft reach with his tendrils, for a total of 55 ft.

On page 292 of the Monster Manual, they give an example of advancing the Otyugh. Ordinarily, it has Space/Reach of 10 ft./10 ft. (15 ft. with tentacles). When it is advanced to size category huge, it has 15 ft./15 ft. (25 ft. with tentacles). This is not the same as reach weapons (as it did not double), nor is it the same as the +5 ft. reach that is normally gained. In fact, there is no similarity to any other size increase that I have seen. That's why I was hoping maybe another source had more information on this. But, it appears not.

[Falontani]

I dont remember where, but I believe that somewhere it stated that whenever you go up a size category reach weapon's reach are doubled (so a spear would go from 10' to 20') but I dont believe it stated anything about natural reach

[martixy]

On page 292 of the Monster Manual, they give an example of advancing the Otyugh. Ordinarily, it has Space/Reach of 10 ft./10 ft. (15 ft. with tentacles). When it is advanced to size category huge, it has 15 ft./15 ft. (25 ft. with tentacles). This is not the same as reach weapons (as it did not double), nor is it the same as the +5 ft. reach that is normally gained. In fact, there is no similarity to any other size increase that I have seen. That's why I was hoping maybe another source had more information on this. But, it appears not.

Well that's amusing. It isn't even multiplicative as an increase of 50% would grant it +7.5 ft reach, which would round down to 5 ft again.
It appears not indeed. Rules Compendium is mum on the issue too.

[ViperMagnum357]

Only relevant thing I can think of is the Voidmind creature template from MM3, which gains a single tentacle that possesses a dynamic reach that is always 5 feet longer than the creature's natural reach. Which by RAW will change to accommodate size alterations via effects, to always remain natural reach +5 feet; even in a situation with things like class features or feats like Inhuman Reach.

Based on the only example I can find, I would probably rule the strands to be a static bonus to reach that gets resized when the creature does-so 50ft-10ft=40ft of extra reach, so at Huge would be 55ft of reach. Not sure what else to do, really, in lieu of other examples.

[InterstellarPro]

Well that's amusing. It isn't even multiplicative as an increase of 50% would grant it +7.5 ft reach, which would round down to 5 ft again.
It appears not indeed. Rules Compendium is mum on the issue too.

Maybe it is the +50%. But for size categories at least small, you round up. For Tiny or below, you round down?

[TallerSpine]

Maybe it is the +50%. But for size categories at least small, you round up. For Tiny or below, you round down?

Maybe the actual length was 17.5 ft rounded down to 15 ft. Increasing it by 50% would be 26.25 rounded down to 25 ft.

[emeraldstreak]

That's why I was hoping maybe another source had more information on this. But, it appears not.

Nope. The best you can find are the ruins of old flamewars on these questions.