think your idea is right. For April Fool's Day, you should give a funny gift. This way, it is thoughtful and your girlfriend will like it very much. As for what to give, I can give you some advice.
Last April Fool's Day, my boyfriend gave me a real doll. But do you know what this doll looks like? It looks very similar to me, but it looks very funny. It sings with great joy and squats to sing. When I saw it, I was stunned. I am usually a very quiet and well-behaved girl. I give people the impression of being well-educated and well-mannered. The doll's appearance is killing me. I guess I can't do it, but the doll shows it. Hehe, although I don't know whether to laugh or cry, I like it very much. I still keep it well now. It is really very individual. You can also try it and make it a different side of your girlfriend. I believe she will like it.
In addition to the doll, you can also give a color-changing sun jar. When you place the sun jar in the sunlight during the day, it will automatically collect the sunlight, and at night it will automatically release soft light. It is a fashionable and fun April Fool's Day gift, highly recommended!