Hello, Ricci!
Both Enraged Morshabaal and Furious Morshabaal are versions part of the Morshabaal mechanics.
There is a counter next to Morshabaal name, which starts at 25 with a green icon and decreases 1 per second. When it reaches 0, a new counter appears, red and from 5 to 0. If Morshabaal is attacked during the red symbol, it will change to its next stronger form.
Enraged Morshabaal reflects lots of damage and take less damage. It is possible, though, to still cause some damage. On furious form the reflect is so big that you'll make almost no damage and take lots of damage instead.
Source: Tibia Fandom