Upon entering the body, Bloat causes the victim to swell in size, causing some damage (although the amount is somewhat inconsistent). The victim may also explode, causing them to die. A victim who is under the effects of bloat shouldn't be able to move through any doors without causing damage to themselves.
Bloat poison is created in a poison lab from blowfish poison sacs. Blowfish can be found in Tuna Bay, and also in the Ninja Guild pond, with the latter requiring some amount of co.st.un and cr.hu.fi to succeed. Like Spider poison it does not require any other ingredients.