M-U Effects

Aside from the mental trauma and a wound on the left side of his head, Scar has some additional souvenirs from his M-U Trail. The point of the M-U trial was to not only completely crush his pride, to rub in how he is a shitty King and that Mufasa is better etc., and to exploit his mental weaknesses. But there are also some effects that last a while longer, which toy with what little advantages the poor lion had in Landels'. The mentioned advantages are (were?) mainly his intelligence and his senses.

Senses
Even placed into a human form, Scar had been in the possession of better senses. Though dampened, he could smell, see and hear better than a human, at least. After his M-U, his senses will become unreliable. At random intervals, one of these three senses will either be reduced to a human level or stop working entirely for unspecified lengths of time. It may be brief, it may be half of the night.

The improved senses are (were?) also one of the few things that remain(ed?) of his original form, and that very connection has now been tampered with.

Intelligence
The next souvenir is something that has been done to his intelligence, but is a little more subtle. It's his most prominent strength, but after his M-U, even his brain has become unreliable. At random intervals, he will be drawing so-called blanks. Like not being able to make connections, have a serious lapse in judgment, that sort of stuff, in situations where he'd otherwise have complete control. He will also realize this at the time.

This will cause some additional paranoia once he realizes what exactly has been done to him, as there's no way for him to predict these random intervals.