I just reached act II Sirocco's cave and the bil / gall / fel spewer (some kind of !@#$ on the wall with a lot of holes) shoot projectiles that are not slowed by the Time Slow spell from the Wizard.

My game is in french this is why I roughly translated the name of the monster.
for more precision
Zone: Grotte du Sirocco
monster: Cracheur de bile