Binbag's Greasy Disaster

Slick, sticky grease covers the ground in a 20ft radius circle centred on the caster and turns it into difficult terrain for the duration.

When the grease appears, each creature standing in its area must succeed on a Dexterity saving throw or fall prone. Additionally, they drop any items they're holding and must make an Acrobatics or Athletics against your spell save DC to retrieve it. A creature that enters the area or ends its turn there must succeed on a Dexterity saving throw or fall prone. 

The caster's spell save DC is increased by 2 for any checks or saves made against this spell as they channel the chaotic energies of Binbag, The Great and Powerful.