If a unit of Screamers moves over one or more unengaged enemy units in the Remaining Moves sub-phase, choose one of those units – it suffers D3 Strength 4 attacks per Screamer. These attacks hit on a 4+ and are treated as shooting attacks.
Source: Warhammer Armies Project: Unofficial 9th Edition (v2.2)
If a unit of Screamers moves over one or more unengaged enemy units in the Remaining Moves sub-phase, choose one of those units – it suffers D3 Strength 4 attacks per Screamer. These attacks hit on a 4+ and are treated as shooting attacks.