In Guildmaster's Guide to Ravnica there is an enemy, Horncaller, who has an interesting ability:
One with the Worldsoul. The horncaller chooses one beast it can see within 30 feet of it. If the beast can hear the horncaller, the beast uses its reaction to make one melee attack against a target that the horncaller can see.
—Horncaller, Guildmaster's Guide to Ravnica, pg. 253
According to the question linked at the bottom, it seems that a Druid using Wild Shape is in fact a Beast during that time. Can the horncaller force the Druid to use its reaction to attack an ally?
(Link for reference: Is a druid in wild shape actually a beast? )