Trigger to temporary change model used by unit

Trigger to temporary change model used by unit

If i, for example, wanna turn a hero into a sheep for, say, 3 seconds, how do i do that with a trigger?

Searched under actions; animation, unit.

And now i mean to just change the model, how it looks, not the whole unit...

You have 2 ways:
1) Replace unit for 3 seconds and replace it back.
2) Create invisible unit with modified Hex ability of range 99999 and cast time 0 and order it to cast this spell on attacking unit.