These were not 'cards' per se but illustrated paper items folded to fit into a standard-size card pack. The conceit of the issue was that they could be personalized and given to a recipient, who would unfold the item and read the gag, thereby becoming the object of the joke.
The Nasty Notes were fully illustrated in color, on both sides, with one panel available for writing the recipient's name. They were also numbered.
One of the artists on this series may have been Wally Wood, who is known to have done work for Topps during that time.
Note: There was another Topps release four years later called Nasty Valentine Notes that was very similar to this one.