Basically, you can slow it down before it hits the object.
Warning "OR" is somewhat buggy, but it seems to work fine in this case.
+ Sprite2: overlaps "Solid" : offset (-5,0)
+ System: OR
+ Sprite2: overlaps "Solid" : offset (5,0)
+ System: OR
+ Sprite2: overlaps "Solid" : offset (0,5)
+ System: OR
+ Sprite2: overlaps "Solid" : offset (0,-5)
-+ System: Trigger once
--> Sprite2: Set speed to 10