How did the Samaritan see Gabriel (peace be upon him) while being a human, and humans do not see angels in their true form? And has it been mentioned in any of the interpretations that the Samaritan is the Dajjal?

The interpretation of the incident of the Samaritan and his seeing of Gabriel (peace be upon him) contains several opinions:

1. That he saw Gabriel by God's permission for a divine wisdom, and this is not impossible. 2. That he did not see Gabriel himself, but rather saw the effect of his horse's hoof, and this is confirmed by narrations from the Companions and the Successors. 3. That if we assume he saw Gabriel, he might have seen him in a formed shape and not his true form, just as Gabriel appeared to the Prophet (peace be upon him) in the form of a Bedouin. 4. Some scholars have gone to the extent of saying that the verses do not speak of seeing Gabriel or his horse, but rather the Samaritan told Moses that he "perceived what they did not perceive" concerning the matter of crafting the calf, and that he took something from Moses's way and religion and cast it away, meaning he abandoned it.

As for linking the Samaritan to the Antichrist (Dajjal), it is an interpretation not based on sound evidence, and the verse that speaks of the Samaritan's appointment refers to the Day of Judgment.