Formally, there are some versions of the HTML standard in which this would constitute a termination (any -- puts the parser in a state where any > will end the tag) but still be an invalid tag.
Not my understanding. In origin, a comment in HTML is one or more SGML comments (which start and end with two dashes) contained in a null tag (<!>), with possibly white space as well; the ! before Jeph's closing > violates this syntax. The only way to get it right is to count the dashes in pairs of pairs (ignoring other characters, including single dashes, between alternate pairs, and accepting the > at the right point; many browsers even now do not do this exactly. The W3C HTML4.01 definition demands that there be no space between the opening <! and --, but allows space (only) between the closing -- and >; in XML, and hence XHTML, the close of the tag may no longer be divided by a space. In real life, using <!-- and --> and being careful not to have any -- or > in between should avoid pitfalls. This all has curious effects, like <!------------> is a valid comment, but <!-------------> is not (not a multiple of four dashes), so be careful when making dash separators in HTML!
Not to forget the comic, in earlier comics, Pintsize could just be
pulled apart at the joints without damage (
"contained-field magnetics"); but this time there seem to be wires at his joints - not that breaking them has stopped his "brain" (which has always continued to function when separated from his body).