Note that Umôrdhoth doesn't have the Monster trait, so it will not take increased damage from Lita Chantler.
Note that the action ability here is not a Parley, so you will get hit by an attack of opportunity when using it, and your investigator can be defeated before that action resolves.
- If an enemy is “considered” engaged with you because of the Massive keyword, it will enable abilities – like the Machete’s – that require you to be engaged with an enemy. However, there is no timing point of engagement, you’re just “considered” engaged with it, so you can’t really trigger reactions to becoming engaged with the enemy, like Zoey Samaras or Zoey's Cross.
Der Verschlinger aus der Tiefe
Großer Alter. Elite.
Umôrdhoth bekommt pro Ermittler +4 Ausdauer.
Erzwungen - Am Ende des Zuges jedes Ermittlers: Mache Umôrdhoth spielbereit.
Falls du Lita Chantler kontrollierst: „Es ist nur hinter ihr her!” Du schleuderst Lita Chantler in Umôrdhoth Richtung, um dein Leben zu retten. (→A3)
The FAQ provide a good explanation of why this last scenario is usually not much loved. Basically almost anything that you could try to shorten the massive amount of beating that the investigators stand to receive (3 damages and 3 horrors per each per round...) is disabled: no Lita,
no Machete, no Cross... (Edit: the Machete works, it was an error on my part. Of course it has been duly taboo-ed but against this enemy one is fully allowed to disregard the taboo list, in my opinion!)
So, not only you have a huge, huge enemy, which was expected: but all of your "smart ideas" are frustrated.
It may hammer the point home... But is not a lot of fun.