Kids bday gift question

My son (4yo) has a best friend who is turning 5. We got him a lil toy that my son's obsessed with (weird little alien thing that you dissect to get the other toy out, it has slime and it's just generally gross).

But I found out his mom doesn't typically allow slime in their house but said it's fine when I asked her. I know she would prefer not having it bc she runs a daycare...but her son would like it a lot and my son picked it out so it would disappoint both kids.

This might sound dumb but do I get a different toy or just give that one?