On the topic of prodrugs, now I find them everywhere ...
1D-LSD (1-(1,2-dimethylcyclobutane-1-carbonyl)-lysergic acid diethylamide) is a psychotropic substance and a research chemical that has potential psychedelic effects.
It is believed to be a prodrug for LSD and has replaced 1V-LSD in Germany after 1V-LSD became covered by the German NpSG law in 2022.
https://en.m.wikipedia.org/wiki/1D-LSDPersonal reports, however, indicate some inferior differences between it and it's metabolite.