Burning

Itachi looked down on him coolly. “This is for Shisui.”
“W-WAIT ... ”
“Amaterasu,” he murmured.
A black flame sprouted on Sugaru’s shoulder. The strange blaze spread, in
the blink of an eye, to swallow his entire body. As if trying to abandon their
burning host, the insects fled from every hole, but they were all caught up in
the dark blaze.
“This fire will not go out until whatever I’m looking at has completely
burned up. I won’t let even one of the insects nesting in you escape.”
Sugaru’s cries of agony rang out through the forest. Around him, insects
buzzed and fluttered, shrouded in dark flames. They looked almost like black
fireflies that bloomed in the daytime.

Book of Dark Night Chapter 6 Part 7