That panel always reminds me of this one. There's a lot of [[plot]] that leads up to pic related but the basic context is:>Anton Arcane is Swamp Thing's nemesis>He was "killed" once in his original appearance, then seemingly killed again multiple times before being ultimately and finally obliterated and sent to hell, with an entire issue being dedicated to Swamp Thing verifying that he was, in fact, truly dead>He promptly escapes as a spirit and possesses Matthew Cable, Swamp Thing's friend (and also the guy married to his future girlfriend). Come to think of it this may have literally been the next issue.
Swamp Thing has no idea that this has happened, and has previously verified beyond a shadow of a doubt that Arcane was dead, and yet he doesn't miss a beat during this interaction and immediately knows exactly who would be fucking with him like that. He doesn't even question how it happens, he's just so used to Arcane pulling shit like this. Arcane is like Swamp Thing's Black Manta.