Golden dart frog
"In a 20-gram white mouse, the minimal lethal dose of batrachotoxin/homobatrachotoxin is about 0.05 µg, when injected subcutaneously. Thus, one frog, P. terribilis, with typical 1100 µg of these compounds, contains enough poison to kill more than 20,000 mice. Although extrapolating toxicity parameters from mouse to man has errors, if we suppose that man is at least as susceptible as mice to these compounds, the lethal dose is about 180 µg for a person. Larger animals are often more susceptible to toxins that smaller organisms, so that the lethal dose for man may be even less. Myers et al. [1] anticipated a lethal dose of batrachotoxin for man of only 2.0 to 7.5 µg, when administered by injection.