Methinks the butter could be considered a deadly weapon, based on what we
now know. This is from Izaak Walton, year 1653:

"First, open your Pike at the gills, and if need be, cut also a little slit
towards the belly. Out of these, take his guts; and keep his liver, which
you are to shred very small, with thyme, sweet marjoram, and a little
winter-savoury; to these put some pickled oysters, and some anchovies, two
or three; both these last whole, for the anchovies will melt, and the
oysters should not; to these, you must add also a pound of sweet butter,
which you are to mix with the herbs that are shred, and let them all be well
salted. If the Pike be more than a yard long, then you may put into these
herbs more than a pound, or if he be less, then less butter will suffice:
These, being thus mixt, with a blade or two of mace, must be put into the
Pike's belly; and then his belly so sewed up as to keep all the butter in
his belly if it be possible; if not, then as much of it as you possibly can.
But take not off the scales. Then you are to thrust the spit through his
mouth, out at his tail. And then take four or five or six split sticks, or
very thin laths, and a convenient quantity of tape or filleting; these laths
are to be tied round about the Pike's body, from his head to his tail, and
the tape tied somewhat thick, to prevent his breaking or falling off from
the spit. Let him be roasted very leisurely; and often basted with claret
wine, and anchovies, and butter, mixt together; and also with what moisture
falls from him into the pan. When you have roasted him sufficiently, you are
to hold under him, when you unwind or cut the tape that ties him, such a
dish as you purpose to eat him out of; and let him fall into it with the
sauce that is roasted in his belly; and by this means the Pike will be kept
unbroken and complete. Then, to the sauce which was within, and also that
sauce in the pan, you are to add a fit quantity of the best butter, and to
squeeze the juice of three or four oranges. Lastly, you may either put it
into the Pike, with the oysters, two cloves of garlick, and take it whole
out, when the Pike is cut off the spit; or, to give the sauce a haut goût,
let the dish into which you let the Pike fall be rubbed with it: The using
or not using of this garlick is left to your discretion."

This dish of meat is too good for any but anglers, or very honest men; and I
trust you will prove both, and therefore I have trusted you with this
secret.'