Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I must eat. devour you must eat. devour he must eat. devour we must eat. devour you must eat. devour they must eat. devour
V-ing form
I must be eat. devouring you must be eat. devouring he must be eat. devouring we must be eat. devouring you must be eat. devouring they must be eat. devouring
Perfect
I must have eat. devoured you must have eat. devoured he must have eat. devoured we must have eat. devoured you must have eat. devoured they must have eat. devoured
V-ing perfect
I must have been eat. devouring you must have been eat. devouring he must have been eat. devouring we must have been eat. devouring you must have been eat. devouring they must have been eat. devouring
Negation
Simple form
I mustn't eat. devour you mustn't eat. devour he mustn't eat. devour we mustn't eat. devour you mustn't eat. devour they mustn't eat. devour
V-ing form
I mustn't be eat. devouring you mustn't be eat. devouring he mustn't be eat. devouring we mustn't be eat. devouring you mustn't be eat. devouring they mustn't be eat. devouring
Perfect
I mustn't have eat. devoured you mustn't have eat. devoured he mustn't have eat. devoured we mustn't have eat. devoured you mustn't have eat. devoured they mustn't have eat. devoured
V-ing perfect
I mustn't have been eat. devouring you mustn't have been eat. devouring he mustn't have been eat. devouring we mustn't have been eat. devouring you mustn't have been eat. devouring they mustn't have been eat. devouring
Interrogative form
Simple form
must I eat. devour? must you eat. devour? must he eat. devour? must we eat. devour? must you eat. devour? must they eat. devour?
V-ing form
must I be eat. devouring? must you be eat. devouring? must he be eat. devouring? must we be eat. devouring? must you be eat. devouring? must they be eat. devouring?
Perfect
must I have eat. devoured? must you have eat. devoured? must he have eat. devoured? must we have eat. devoured? must you have eat. devoured? must they have eat. devoured?
V-ing perfect
must I have been eat. devouring? must you have been eat. devouring? must he have been eat. devouring? must we have been eat. devouring? must you have been eat. devouring? must they have been eat. devouring?
Interro-negative form
Simple form
mustn't I eat. devour? mustn't you eat. devour? mustn't he eat. devour? mustn't we eat. devour? mustn't you eat. devour? mustn't they eat. devour?
V-ing form
mustn't I be eat. devouring? mustn't you be eat. devouring? mustn't he be eat. devouring? mustn't we be eat. devouring? mustn't you be eat. devouring? mustn't they be eat. devouring?
Perfect
mustn't I have eat. devoured? mustn't you have eat. devoured? mustn't he have eat. devoured? mustn't we have eat. devoured? mustn't you have eat. devoured? mustn't they have eat. devoured?
V-ing perfect
mustn't I have been eat. devouring? mustn't you have been eat. devouring? mustn't he have been eat. devouring? mustn't we have been eat. devouring? mustn't you have been eat. devouring? mustn't they have been eat. devouring?