I don’t want to reiterate what appears in the Triton catalogue on this specimen, as you can read it yourself by clicking on the image. In the article I linked to earlier today, Callataÿ mentioned the phenomenon of these coins of a “pretender” to the Macedonian throne being overstruck on denarii.
The one above is apparently using this type as its flan:
The Crawford type is re-dated by the overstrike, just pushed down a couple of years. It’s striking [always my favorite numismatic pun] that two of the known specimens of Andriscus are known to have been overstruck on the this same type. Here’s the link to the other one. The obverse dies are linked but the reverses are unique. Another un-die-linked specimen is overstruck on a Thesalian League type. Of course, Callataÿ is right that it shows use of the denarius in the East, at least sufficient to allow Andriscus to produce a (small?) series.
The other minor mystery is whatever is Andriscus wearing on his head. Macedonian head gear is always a wee bit baffling, but more on that some other time: