If the target permanent is an illegal target by the time Maelstrom Pulse tries to resolve, the spell won't resolve
Enter the combat phase and put yourself in the declare blockers step: Did you look at the attacking 4/4 and think 9 was a safe life total
Then, if the enchanted creature dies, you get to return this enchantment to the battlefield at the beginning of the next end step
That was, for example, one of the reasons I pulled Mindslaver out of the mothballs and tried to finally get it printed
Spider-Man : During her stay in an alternate dimension during The Amazing Spider-Man (2022) , Mary Jane is able to create a device that randomly combines magical symbols to, in essence, improvise spells on the spot
We look forward to seeing you there