is a "30 gram ball" some kind of archeaic unit? 30/5000 = 1/166 != 23/300 = 1/13.
but anyway, I feel this ruling would open an even better exploit the other way. Shoot an enlarged half-gram grain of sand weighing 30 gram at 300 meters per second, when it travels through the ring it will reduce down to it's original size increasing speed to 19.2 km/s, having a new kenetic energy of 92 megajoules or 22kg of tnt.
In dnd terms that's maybe 6d6 fire damage, range 10/30.
Also the quantity of milk/ eggs produced by cows and chickens is only so high due to millenia of selective breeding by humans, so was there a eugenicist milk aficionado in beastars universe?
I am picturing a non-instanteous transmutation, as seen in Harry Potter etc... (DnD would also count spells like "true polymorph" having a casting time of 1 action (~6second).)
Not a barotrauma specialist, so can't comment on instantaneous case.
A particularly healthy set of lungs contains 4litres (5 grams) of air, assuming a conservation of mass, that's less than one ml of silver, being a noble metal, the silver harmlessly disapates into the theifs bloodstream over the next couple years, at worst turning them blue. The awakened mushroom sorcerer hidden in the theifs pocket casts an actually good spell, such as fireball.
what did you get banned for saying?