art credit @milksapp-the-waxy-conifer-aphid
I'm an anthropomorphic Atlantic bluefin tuna (Thunnus thynnus).
Internal thermal control.
Flat hard limbs (including tailfin) somewhat blade-like.
Special Ability: Methylmercury H3C-Hg+ control.
Stratified mercury via carbon chains is not even science-fiction.
Given tuna biology and human intellect it's possible with practice.
Mercury forms lattices
that shift between being spherical and rod-like.
used the right way and these can grab or ensnare.
Lattices can be laced with safe levels of methylmercury,
which permeates through clothing
and has various effects on mind.
Mercury lattices are vulnerable to heat.
Thermal control helps a little with heat weakness.
But not against something like an open flame.
Limited supply of mercury makes it high risk to high reward.
Essentially, if I spill mercury, i have to collect it again.