Force Effects for D&D

[Guinaur]

I made this "effect" for my dnd sessions and would like to share it here.
I felt that the Bull Rush and Trip effects were a bit underused and desided to do something with them.

Note: This is not a spell, but an effect that can be used to make a spell.

Basically, a force effect is a "mass" of force that has three characteristics: a Strength score, a Speed score, and a Size catagory. When a "force effect" hits a creature, it automatically moves into the creatures space, and attempts a Bull rush against the creature. The "force effect" always chooses to move with the target. If the Bull Rush succeeds, the "force effect" then tries to Trip the creature. If the Trip succeeds, the "force effect" either stops or continues moving (depending on its origins). This effect is usefull for spells and weapon enchantments.

An example of a spell:

Force Blast
Evocation (Force)
Level: Sor/Wis 2
Components: V,S
Casting Time: 1 action
Duration: Instantanious
Range: Close (25ft + 5ft/2lvl's)
Area: 5ft - line
Saves: Force Effect
SR: no

This spell evokes a force effect with the following characteristics: Str 10+caster level (max: +15); Speed: 25ft + 5ft/2lvl's; Size: Medium