horse
Explanation
This comic is a riff on the Trojan Horse from Greek mythology. Soldiers outside a castle wall discuss strategy, with one saying they should "try nobody just once knocks away a horse's obvious goal." The other panel shows a very poorly drawn, obviously fake wooden horse that the defenders can clearly see through. Yet the caption reveals: "The horse is normally good drawing but for the next 30 minutes is 20% off" -- suggesting the Trojan Horse scheme was essentially a transparent scam, like a phishing email with obvious spelling errors.
The joke compares the Trojan Horse strategy to modern-day internet scams and phishing attempts that are intentionally crude and obvious. Just as some scam emails use poor grammar to filter for gullible targets, the poorly constructed horse only works on defenders dumb enough to fall for it. The comic suggests that the legendary Trojan Horse was less a brilliant military stratagem and more akin to a "Nigerian prince" email -- something so obviously fake that accepting it says more about the victim than the attacker.